Rozprawy doktorskie: „Metabolic responses”

1

Holmbäck, Ulf. "Metabolic and Endocrine Responses to Nocturnal Eating". Doctoral thesis, Uppsala universitet, Institutionen för medicinska vetenskaper, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-2956.

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An increasing amount of people have their work hours displaced to the night and there are indications that shift work and other irregular working schedules are associated with an increased risk of developing the metabolic syndrome and other pathological conditions. It is therefore important to address the consequences of eating at irregular hours, especially nighttime. Papers I-III refer to a study in which 7 males were given a high-carbohydrate diet (HC) or a high-fat diet (HF), using a cross-over design. Subjects were kept awake for 24 h and food was provided as 6 equally spaced isocaloric meals. Higher energy expenditure and non-esterified fatty acids (NEFA) concentration, as well as lower glucose and triacylglycerol (TAG) concentrations were observed with the HF-diet, compared to the HC-diet. With the HF-diet, fat oxidation, heat release, heart rate, glucose, NEFA and TAG concentrations differed depending on time of day. The highest postprandial TAG concentrations were seen after the 04.00 meal with both diets. Insulin and leptin responses to meal intake differed with respect to diet and time of day. Time of day affected glucagon, thyroid stimulating hormone, free thyroxin, total triiodothyronine (tT3), cortisol, chromogranin A and pancreatic polypeptide (PP) concentrations. PP’s postprandial increase was greater during 08.00 – 16.00 compared to 20.00 – 08.00. Furthermore, the subjects felt less irritated when eating the HF-diet but hunger was not related to macronutrient composition. Hunger and thirst decreased throughout the 24 h period despite constant activity and energy intake; and were correlated with several endocrine and metabolic variables. In paper IV 7 males were studied twice during 24-h either given 6 isocaloric meals throughout the 24-h period, or 4 isocaloric meals from 08.00 to 20.00, followed by a nocturnal fast. Energy expenditure, glucose, TAG, insulin and glucagon concentrations were lower; and NEFA concentrations were higher during the nocturnal fast compared to nocturnal eating; although no 24 h differences between the protocols were apparent. The subjects were more passive during the fasting period compared to when food was given. Stepwise regression showed that correlations between metabolic variables and hormones differed between daytime and nighttime. The decreased evening/nocturnal responses of cortisol and PP to meal intake suggest that nocturnal eating might have health implications and that the body reacts unfavorably to nocturnal eating. Smaller meals around the clock, however, showed marginally better effects on postprandial TAG concentrations and mental energy compared to larger meals during daytime. Further studies (long term) are needed before dietary guidelines can be given to shift workers, especially regarding the impact of nocturnal eating on gastrointestinal response and cortisol.

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2

Drust, Barry. "Metabolic responses to soccer-specific intermittent exercise". Thesis, Liverpool John Moores University, 1997. http://researchonline.ljmu.ac.uk/5574/.

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The intermittent exercise pattern associated with soccer makes analysis of the demands of the sport more complex than in many individual sports. The aim in this thesis was to determine the physiological and metabolic responses to soccer-specific exercise. The demands associated with elite level match-play were evaluated by techniques of motion-analysis. Laboratory based soccer-specific intermittent exercise protocols were then devised to determine the physiological strain associated with soccer and investigate the effects of increased ambient temperature and whole body pre-cooling on performance. The work-rate profiles of elite South American soccer players and English Premier League players, performing in international and club level respectively, were determined. English Premier League players covered a greater total distance during a game than the South American players (P< 0.05). Differences were found for the total distance covered for playing positions with midfield players covering larger distances than forwards. Defenders covered a greater distance jogging backwards than forward players with forwards sprinting a greater distance than defenders. Work-rate was reduced in the second half of the game for all player. The total distance covered by the international players was done mainly at submaximal intensities. High intensity exercise was infrequent and bouts were of short duration. No significant correlations were observed between the work-rate profile and anthropometric charactersitics of individuals. The use of the doubly-labelled water technique to indicate the energy expenditure during soccer match-play was investigated. The doubly-labelled water technique cannot determine energy expenditure during a soccer match as the rate of turnover of the isotopes is too small to allow the accurate estimation of energy expended. Laboratory based soccer-specific intermittent protocols elicited physiological responses that were similar in magnitude and pattern to soccer match-play. Physiological demands fluctuated with exercise intensity during intermittent exercise. Oxygen consumption and heart rate were not significantly different during soccer-specific intermittent exercise and steady-rate exercise at the same average intensity. Rectal temperature did not differ significantly between the two protocols, although intermittent exercise performance resulted in a greater rise in rectal temperature as the protocol progressed (P< 0.05). Sweat production did not differ significantly between the two exercise sessions, though the rating of perceived exertion was significantly higher (P< 0.05), for the session as a whole, during intermittent exercise. Intermittent exercise performance at 26 ° C did not result in significant increases in the physiological, metabolic or thermoregulatory responses when compared to intermittent exercise at 20 ° C. The physiological and metabolic responses were also similar when intermittent exercise was performed after a whole body pre-cooling manoeuvre. Rectal temperature was lowered by the pre-cooling strategy prior to exercise (- 0.6 ± 0.6 ° C, P< 0.05). Rectal temperature during exercise was only significantly lower after pre-cooling than during exercise at 26 ° C. No significant differences were observed in rectal temperature during exercise between the normal and pre-cooled condition. The increase in rectal temperature during the second half of the protocol was significantly greater than the increase observed at 26 ° C or under normal conditions. This may be a consequence of an altered thermoregulatory response due to the pre-cooling manouvre. In conclusion, the work-rate demands of soccer seem to be predominantly aerobic in nature with anaerobic bouts and the performance of specific match activities increasing the demands placed on players. The demands of intermittent exercise are not significantly different from continuous work performed at the same average intensity though there is tentative evidence for a decrease in the efficiency of the thermoregulatory system during intermittent work. No adverse effects upon intermittent exercise performance were noted under conditions of moderate heat stress, while any thermoregulatory benefits of whole body pre-cooling during intermittent work are probably only transient.

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3

Steel, Helen Carolyn. "Metabolic responses to in vitro zinc supplementation". Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1004101.

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The present study was carried out to determine the effects and possible mechanism of action of zinc supplementation on the in vitro growth of malignant murine melanoma (B16) and non-malignant monkey kidney (LLCMK) cells. Cell culture studies showed that zinc supplementation significantly inhibited B16 growth at all the concentrations studied (1, 3, 5 and lOμg/ml). Zinc was also found to inhibit the growth of the LLCMK cells, although to a lesser extent than the B16 cells. Possible evidence of mobilisation of the essential fatty acids from the membrane phospholipid stores was noted in both cell types. This effect was, however, greater in the B16 cells. Δ⁶-desaturase activity was found to be significantly lower in the B16 cells than in the LLCMK cells (p ≥ 0.05). Zinc supplementation resulted in an increase in the enzymes activity in the LLCMK cells and, at high concentrations, in the B16 cells. An estimation of elongase and Δ⁶-desaturase activity with zinc supplementation indicated that zinc had little or no effect on the activity of these enzymes. B16 cells were found to have higher levels of free radicals than the LLCMK cells. Zinc supplementation resulted in increased free radical formation in the B16 cells, while no effect was observed in the LLCMK cells. Lipid peroxidation increased in both cell types with increased zinc concentrations. The observed effect of zinc supplementation on cell growth may involve these elevated levels of lipid peroxides. CycIo-oxygenase activity was found to be greater in the B16 cells than the LLCMK cells. The activity of the enzyme increased with higher concentrations of zinc (lOμg/ml) in both cell types. Prostaglandin E, levels were found to be lower in the B16 cells compared to the LLCMK cells. The levels of prostaglandin E, in both cell types appeared to be dependent on the levels of the polyunsaturated fatty acid precursors to the prostaglandins. Zinc was found to inhibit the activity of the enzyme adenylate cyclase in both cell types. The cAMP levels in the LLCMK cells were also found to decrease with zinc supplementation. In the case of the B16 cells, cAMP levels increased at low concentrations of zinc despite a decrease in adenyl ate cyclase activity, suggesting a possible inhibition of cAMP phosphodiesterase activity at these concentrations of zinc. It is concluded that although zinc supplementation does have an effect on cell growth, this effect is not mediated through the activation of adenylate cyclase by the prostaglandins resulting in elevated levels of cAMP. A possible mechanism involving lipid peroxidation is proposed.

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4

Weber, Clare L., i n/a. "Metabolic Responses to Supramaximal Exercise and Training: A Gender Comparison". Griffith University. School of Physiotherapy and Exercise Science, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030407.155407.

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The primary aim of this thesis was to investigate the gender-specific responses to supramaximal cycling and to examine the changes in anaerobic and aerobic metabolism that occur in response to high-intensity interval training (HIT). All subjects in the present experiments were untrained, healthy young adults aged between 18 and 35 yr. Cycle ergometry was used for all experimental test procedures and training programs. The accumulated oxygen (AO2) deficit was used to quantify the production of adenosine triphosphate (ATP) via anaerobic metabolism during supramaximal cycling. In addition, pulmonary oxygen uptake measured at the onset of exercise was described using mathematical modeling to determine the rate response of the aerobic energy system during exercise. The purpose of experiment one was to examine the test-retest reliability of the maximal accumulated oxygen deficit (MAOD) measured at 110% and 120% of peak oxygen uptake for cycling in seven untrained male and seven untrained female subjects. After one familiarization trial, all subjects performed two MAOD tests at a power output corresponding to 110% and two tests at 120% of peak oxygen uptake in random order. MAOD was calculated for each subject as the difference between the estimated AO2 demand and the AO2 uptake measured during the exercise bout. The mean±standard error time to exhaustion (TE) for the group was not significantly different between trial one (226±13 s) and trial two (223±14 s) of the 110% test. Likewise, the difference in the TE between trial one (158±11 s) and trial two (159±10 s) was not significant for the 120% test. The intra-class correlation coefficients for the TE were 0.95 for the 110% test and 0.98 for the 120% test. The mean MAOD value obtained in trial one (2.62±0.17 L) was not significantly different from the mean value obtained in trial two (2.54±0.19 L) for the 110% test. Additionally, the mean values for the two trials did not differ significantly for MAOD (2.64±0.21 L for trial one and 2.63±0.19 L for trial two) in the 120% test. The intra-class correlation coefficients for MAOD were 0.95 for the 110% test and 0.97 for the 120% test. All intra-class correlation coefficients were significant at p < 0.001. When conducted under standardized conditions, the determination of MAOD for cycling was highly repeatable at both 110% and 120% of peak oxygen uptake in untrained male and female subjects. The results observed in experiment one suggest that the MAOD may be used to compare the anaerobic capacity (AC) of men and women and to examine changes in the contribution of the anaerobic energy systems before and after training. Experiment two examined the gender-specific differences in MAOD before and after 4 and 8 wk of HIT. Untrained men (n=7) and women (n=7) cycled at 120% of pre-training peak oxygen uptake to exhaustion (MAOD test) pre-, mid-, and post-training. A post-training timed test was also completed at the MAOD test power output, but this test was stopped at the TE achieved during the pre-training MAOD test. The 14.3±5.2% increase in MAOD observed in males after 4 wk of training was not different from the 14.0±3.0% increase seen in females (p > 0.05). MAOD increased by a further 6.6±1.9% in males and this change was not different from the additional 5.1±2.3% increase observed in females after the final 4 wk of training. Peak oxygen uptake measured during incremental cycling increased significantly (p < 0.01) in male but not in female subjects after 8 wk of training. Moreover, the AO2 uptake was higher in men during the post-training timed test compared to the pre-training MAOD test (p < 0.01). In contrast, the AO2 uptake was unchanged from pre- to post-training in female subjects. The increase in MAOD with training was not different between men and women suggesting an enhanced ability to produce ATP anaerobically in both groups. However, the increase in peak oxygen uptake and AO2 uptake obtained in male subjects following training indicates improved oxidative metabolism in men but not in women. It was concluded that there are basic gender differences that may predispose males and females to specific metabolic adaptations following an 8-wk period of HIT. Increases in AO2 uptake during supramaximal cycling demonstrated in men after training led to the hypothesis that peak oxygen uptake kinetics are speeded in male subjects with short-term HIT. It was suggested that training does not improve peak oxygen uptake kinetics in women as no change in AO2 uptake was found after 8 wk of HIT in female subjects. The purpose of experiment three was to examine peak oxygen uptake kinetics before and after 8 wk of HIT in six men and six women during cycling at 50% (50% test) and 110% (110% test) of pre-training peak oxygen uptake. A single-term exponential equation was used to model the peak oxygen uptake response (after phase I) during the 50% and 110% tests pre- and post-training. In addition, phase II and III of the peak oxygen uptake response during the 110% tests were examined using a two-term equation. The end of the phase I peak oxygen uptake response was identified visually and omitted from the modeling process. The duration of phase I determined during all experimental tests was not different between men and women and did not change with training in either group. Before training, men obtained a phase II peak oxygen uptake time constant (t2) of 29.0±3.3 s during the 50% test which was not different to the t2 of 28.8±2.2 s attained by women. In addition, the t2 determined during the 50% test was unchanged after 8 wk of HIT in both groups. The peak oxygen uptake kinetics examined during the 110% tests before training were well described by a single-term model in all male and female subjects. The t2 determined before training for the 110% test was significantly faster in men than in women. Furthermore, peak oxygen uptake was unchanged in female subjects and the t2 remained unaltered with 8 wk HIT (pre 45.5±2.2; post 44.8±2.3 s). In contrast, male subjects achieved a significantly higher peak oxygen uptake after training and the t2 determined for men during the 110% test was faster after training (36.4±1.6 s) than before training (40.1± 1.9 s). Improved model fits were obtained with the two-term equation compared to the single-term equation in two of the six male subjects during the 110% test post-training. It was found that the onset of the peak oxygen uptake slow component occurred at a mean time of 63.5±2.5 s and the t2 was reduced to 18.4±1.7 s. Using a Wilcoxon Signed Ranks z-test, the t2 described by the single-term equation in the remaining four subjects was determined to be significantly faster after training than before training, thus confirming the results obtained from the original group (n=6) of male subjects. End exercise heart rate (HREE) values obtained during the 50% and 110% tests were not different between men and women. During the 50% test, HREE values were unchanged, whereas HREE was significantly decreased during the 110% test after training in both groups. These data show that HIT might improve oxidative metabolism in men but not in women as reflected by a greater peak oxygen uptake and faster peak oxygen uptake kinetics during supramaximal work rates. We further suggest that the faster peak oxygen uptake kinetics demonstrated in men after training are probably not due to an improvement in cardiac function. Finally, the augmentation of oxidative metabolism during exercise after HIT in men might be dependent on the intensity of the exercise bout at which the peak oxygen uptake response is examined. The findings presented in this thesis suggest that MAOD is a reliable measure in both male and female subjects and can be used to monitor changes in anaerobic ATP production during supramaximal cycling. Moreover, these data suggest that 4 and 8 wk of HIT produce similar changes in anaerobic ATP generation in men and women. Finally, 8 wk of HIT results in the increase of peak oxygen uptake and AO2 uptake as well as the speeding of peak oxygen uptake kinetics during supramaximal cycling in male subjects. There was no evidence to suggest that oxidative metabolism was improved in women after short-term HIT. In conclusion, improvement in supramaximal exercise performances should be examined specifically for changes in the anaerobic and aerobic contributions to energy production. In addition, it is suggested that gender should be of primary consideration when designing exercise-training programs where improvement in both anaerobic and aerobic metabolism is required.

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5

Weber, Clare L. "Metabolic Responses to Supramaximal Exercise and Training: A Gender Comparison". Thesis, Griffith University, 2003. http://hdl.handle.net/10072/366993.

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The primary aim of this thesis was to investigate the gender-specific responses to supramaximal cycling and to examine the changes in anaerobic and aerobic metabolism that occur in response to high-intensity interval training (HIT). All subjects in the present experiments were untrained, healthy young adults aged between 18 and 35 yr. Cycle ergometry was used for all experimental test procedures and training programs. The accumulated oxygen (AO2) deficit was used to quantify the production of adenosine triphosphate (ATP) via anaerobic metabolism during supramaximal cycling. In addition, pulmonary oxygen uptake measured at the onset of exercise was described using mathematical modeling to determine the rate response of the aerobic energy system during exercise. The purpose of experiment one was to examine the test-retest reliability of the maximal accumulated oxygen deficit (MAOD) measured at 110% and 120% of peak oxygen uptake for cycling in seven untrained male and seven untrained female subjects. After one familiarization trial, all subjects performed two MAOD tests at a power output corresponding to 110% and two tests at 120% of peak oxygen uptake in random order. MAOD was calculated for each subject as the difference between the estimated AO2 demand and the AO2 uptake measured during the exercise bout. The mean±standard error time to exhaustion (TE) for the group was not significantly different between trial one (226±13 s) and trial two (223±14 s) of the 110% test. Likewise, the difference in the TE between trial one (158±11 s) and trial two (159±10 s) was not significant for the 120% test. The intra-class correlation coefficients for the TE were 0.95 for the 110% test and 0.98 for the 120% test. The mean MAOD value obtained in trial one (2.62±0.17 L) was not significantly different from the mean value obtained in trial two (2.54±0.19 L) for the 110% test. Additionally, the mean values for the two trials did not differ significantly for MAOD (2.64±0.21 L for trial one and 2.63±0.19 L for trial two) in the 120% test. The intra-class correlation coefficients for MAOD were 0.95 for the 110% test and 0.97 for the 120% test. All intra-class correlation coefficients were significant at p < 0.001. When conducted under standardized conditions, the determination of MAOD for cycling was highly repeatable at both 110% and 120% of peak oxygen uptake in untrained male and female subjects. The results observed in experiment one suggest that the MAOD may be used to compare the anaerobic capacity (AC) of men and women and to examine changes in the contribution of the anaerobic energy systems before and after training. Experiment two examined the gender-specific differences in MAOD before and after 4 and 8 wk of HIT. Untrained men (n=7) and women (n=7) cycled at 120% of pre-training peak oxygen uptake to exhaustion (MAOD test) pre-, mid-, and post-training. A post-training timed test was also completed at the MAOD test power output, but this test was stopped at the TE achieved during the pre-training MAOD test. The 14.3±5.2% increase in MAOD observed in males after 4 wk of training was not different from the 14.0±3.0% increase seen in females (p > 0.05). MAOD increased by a further 6.6±1.9% in males and this change was not different from the additional 5.1±2.3% increase observed in females after the final 4 wk of training. Peak oxygen uptake measured during incremental cycling increased significantly (p < 0.01) in male but not in female subjects after 8 wk of training. Moreover, the AO2 uptake was higher in men during the post-training timed test compared to the pre-training MAOD test (p < 0.01). In contrast, the AO2 uptake was unchanged from pre- to post-training in female subjects. The increase in MAOD with training was not different between men and women suggesting an enhanced ability to produce ATP anaerobically in both groups. However, the increase in peak oxygen uptake and AO2 uptake obtained in male subjects following training indicates improved oxidative metabolism in men but not in women. It was concluded that there are basic gender differences that may predispose males and females to specific metabolic adaptations following an 8-wk period of HIT. Increases in AO2 uptake during supramaximal cycling demonstrated in men after training led to the hypothesis that peak oxygen uptake kinetics are speeded in male subjects with short-term HIT. It was suggested that training does not improve peak oxygen uptake kinetics in women as no change in AO2 uptake was found after 8 wk of HIT in female subjects. The purpose of experiment three was to examine peak oxygen uptake kinetics before and after 8 wk of HIT in six men and six women during cycling at 50% (50% test) and 110% (110% test) of pre-training peak oxygen uptake. A single-term exponential equation was used to model the peak oxygen uptake response (after phase I) during the 50% and 110% tests pre- and post-training. In addition, phase II and III of the peak oxygen uptake response during the 110% tests were examined using a two-term equation. The end of the phase I peak oxygen uptake response was identified visually and omitted from the modeling process. The duration of phase I determined during all experimental tests was not different between men and women and did not change with training in either group. Before training, men obtained a phase II peak oxygen uptake time constant (t2) of 29.0±3.3 s during the 50% test which was not different to the t2 of 28.8±2.2 s attained by women. In addition, the t2 determined during the 50% test was unchanged after 8 wk of HIT in both groups. The peak oxygen uptake kinetics examined during the 110% tests before training were well described by a single-term model in all male and female subjects. The t2 determined before training for the 110% test was significantly faster in men than in women. Furthermore, peak oxygen uptake was unchanged in female subjects and the t2 remained unaltered with 8 wk HIT (pre 45.5±2.2; post 44.8±2.3 s). In contrast, male subjects achieved a significantly higher peak oxygen uptake after training and the t2 determined for men during the 110% test was faster after training (36.4±1.6 s) than before training (40.1± 1.9 s). Improved model fits were obtained with the two-term equation compared to the single-term equation in two of the six male subjects during the 110% test post-training. It was found that the onset of the peak oxygen uptake slow component occurred at a mean time of 63.5±2.5 s and the t2 was reduced to 18.4±1.7 s. Using a Wilcoxon Signed Ranks z-test, the t2 described by the single-term equation in the remaining four subjects was determined to be significantly faster after training than before training, thus confirming the results obtained from the original group (n=6) of male subjects. End exercise heart rate (HREE) values obtained during the 50% and 110% tests were not different between men and women. During the 50% test, HREE values were unchanged, whereas HREE was significantly decreased during the 110% test after training in both groups. These data show that HIT might improve oxidative metabolism in men but not in women as reflected by a greater peak oxygen uptake and faster peak oxygen uptake kinetics during supramaximal work rates. We further suggest that the faster peak oxygen uptake kinetics demonstrated in men after training are probably not due to an improvement in cardiac function. Finally, the augmentation of oxidative metabolism during exercise after HIT in men might be dependent on the intensity of the exercise bout at which the peak oxygen uptake response is examined. The findings presented in this thesis suggest that MAOD is a reliable measure in both male and female subjects and can be used to monitor changes in anaerobic ATP production during supramaximal cycling. Moreover, these data suggest that 4 and 8 wk of HIT produce similar changes in anaerobic ATP generation in men and women. Finally, 8 wk of HIT results in the increase of peak oxygen uptake and AO2 uptake as well as the speeding of peak oxygen uptake kinetics during supramaximal cycling in male subjects. There was no evidence to suggest that oxidative metabolism was improved in women after short-term HIT. In conclusion, improvement in supramaximal exercise performances should be examined specifically for changes in the anaerobic and aerobic contributions to energy production. In addition, it is suggested that gender should be of primary consideration when designing exercise-training programs where improvement in both anaerobic and aerobic metabolism is required.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Physiotherapy and Exercise Science
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6

Bales, Juliana. "Metabolic signalling and neuroendocrine stress responses in pregnancy". Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/29065.

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I investigated the relationship between the HPA axis and endocrine factors to adipose tissue storage and appetite regulation during late pregnancy in rats. The responsiveness of the hypothalamic neurones regulating ACTH and hence corticosterone responses to insulin induced hypoglycaemia (IIH) and the orexigenic peptides NPY, orexin and ghrelin were investigated. IIH increased ACTH secretion similarly I both virgin and pregnant rats. Unlike most stressors IIH did not stimulate parvocellular CRH mRNA expression in pPVN neurones but it did increase AVP mRNA expression. The responsiveness of the HPA axis to the orexigenic peptides ghrelin, orexin and NPY given by i.c.v. injection was markedly reduced during late pregnancy. This was at least partly a result of reduced activation of the pPVN neurones, as revealed by reduced stimulation of FOS expression in the pPVN compared with virgin rats given these peptides. ACTH secretory responses were also strongly attenuated in late pregnant rats. In contrast all three orexigenic peptides increased food intake to a similar level in both virgin and pregnant rats. Thus neuroendocrine stress responses to central administration of orexin, NPY and ghrelin are absent during late pregnancy whilst ingestive behavioural responses remain intact. Changes in brain circuitry regulating appetite during late pregnancy were shown by increased FOS activation in the lateral hypothalamic area (LHA), ventromedial hypothalamus (VMH) and dorsomedial hypothalamus (DMH). Supraoptic and magnocellular PVN oxytocin responses to centrally administered NPY were reduced during late pregnancy. Endogenous opioids are involved in the attenuation of HPA axis responses to orexin and NPY during late pregnancy since pre-treatment with the opioid receptor antagonist naloxone reinstated the ACTH response and restored CRH and AVP mRNA responses. Naloxone administration revealed that endogenous opioids facilitate NPY-induced feeding in both virgin and late pregnant rats, but more importantly in late pregnant rats. Naloxone restored a FOS response in the PVN and SON in response to NPY in late pregnant rats indicating that oxytocin neurone responses to NPY are suppressed by endogenous opioids. Basal blood glucose levels were lower in late pregnant rats than in virgins. Ghrelin increased blood glucose levels similarly in both virgin and pregnant rats, whilst NPY and orexin increased blood glucose in only the virgin rats. In conclusion, neuroendocrine stress responses to orexin, ghrelin and NPY are reduced in pregnant rats and this was shown for orexin and NPY to be due to endogenous opioid restraint. Endogenous opioid mechanisms have opposite effects on neuroendocrine stress responses and feeding, which will enhance energy availability for the fetuses at this time. Intact HPA axis responses to IIH will ensure continued glucose supply.

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7

Björklund, Glenn. "Metabolic and Cardiovascular Responses During Variable Intensity Exercise". Doctoral thesis, Mittuniversitetet, Institutionen för hälsovetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-11744.

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Previous research investigating endurance sports from a physiological perspectivehas mainly used constant or graded exercise protocols, although the nature ofsports like cross-country skiing and road cycling leads to continuous variations inworkload. Current knowledge is thus limited as regards physiological responses tovariations in exercise intensity. Therefore, the overall objective of the present thesiswas to investigate cardiovascular and metabolic responses to fluctuations inexercise intensity during exercise. The thesis is based on four studies (Studies I-IV);the first two studies use a variable intensity protocol with cardiorespiratory andblood measurements during cycling (Study I) and diagonal skiing (Study II). InStudy III one-legged exercise was used to investigate muscle blood flow duringvariable intensity exercise using PET scanning, and Study IV was performed toinvestigate the transition from high to low exercise intensity in diagonal skiing,with both physiological and biomechanical measurements. The current thesisdemonstrates that the reduction in blood lactate concentration after high-intensityworkloads is an important performance characteristic of prolonged variableintensity exercise while cycling and diagonal skiing (Studies I-II). Furthermore,during diagonal skiing, superior blood lactate recovery was associated with a highaerobic power (VO2max) (Study II). Respiratory variables such as VE/VO2, VE/VCO2and RER recovered independently of VO2max and did not reflect the blood lactate oracid base levels during variable intensity exercise during either cycling or diagonalskiing (Studies I-II). There was an upward drift in HR over time, but not inpulmonary VO2, with variable intensity exercise during both prolonged cyclingand diagonal skiing. As a result, the linear HR-VO2 relationship that wasestablished with a graded protocol was not present during variable intensityexercise (Studies I-II). In Study III, blood flow heterogeneity during one-leggedexercise increased when the exercise intensity decreased, but remained unchangedbetween the high intensity workloads. Furthermore, there was an excessiveincrease in muscular VO2 in the consecutive high-intensity workloads, mainlyexplained by increased O2 extraction, as O2 delivery and blood flow remainedunchanged. In diagonal skiing (Study IV) the arms had a lower O2 extraction thanthe legs, which could partly be explained by their longer contact phase along withmuch higher muscle activation. Furthermore, in Study IV, the O2 extraction in botharms and legs was at the upper limit during the high intensity workload with nofurther margin for increase. This could explain why no excessive increase inpulmonary VO2 occurred during diagonal skiing (Study II), as increased O2extraction is suggested to be the main reason for this excessive increase in VO2(Study III).

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8

Thorne, Stuart Douglas. "Hepatic responses to metabolic demand in the sheep". Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388520.

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9

Duncan, Benedict. "Metabolic responses to acute and prolonged hypoxic exposure". Thesis, University of Brighton, 2017. https://research.brighton.ac.uk/en/studentTheses/b7ceef66-97ca-4c21-b388-34da9d84ca87.

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This thesis examined the metabolic effects of acute and intermediate hypoxic exposure in humans, specifically, physiological mechanisms associated with weight loss. Namely; increased metabolic rate, changes in substrate oxidation, altered lipid metabolism and changes in taste. Study one assessed the validity and reproducibility of an online gas analyser in normobaric hypoxia [Fraction of inspired oxygen: 0.12 (FiO2:0.12) equivalent to approximately 4,500m] (n=nine; two females, seven males). The MetaMax3x demonstrates good reproducibility between repeated trials. Differences exist between the system and the gold standard Douglas Bag method for measures of oxygen uptake (percent differences of V̇O2; 21%), carbon dioxide production (V̇CO2; 10%) and minute ventilation (V̇E; 5%). The second study investigated the free fatty acid (FFA) and triglyceride (TAG) response to an acute (45 minutes) hypoxic exposure (FiO2: 0.12) (n=10; five females, five males). A greater resting metabolic rate (RMR) (+28 ± 6 kcal.hr-1 ) was observed, through increased carbohydrate (CHO) and fat oxidation. Increased plasma FFA (+54%) and TAG (+26%) were observed, highlighting metabolic perturbations from acute exposure. Study three investigated the metabolic responses to an acute (60 minute) hypoxic exposure (FiO2: 0.12) at rest and a subsequent bout of moderate exercise in normoxia following a high fat meal (n=eight males). Experimental trials included a lipid ingestion prior to a rest period at hypoxia or normoxia followed by moderate intensity exercise (60% heart rate reserve). Control trials consisted of the same protocol without lipid ingestion. Acute, severe hypoxia increased energy expenditure (EE), (+22 ± 11 kcal.hr-1 ) CHO and fat oxidation following exposure. A prior acute bout of severe hypoxia did not alter EE and substrate use during subsequent moderate intensity exercise. An exercise bout, postlipid ingestion, resulted in lower triglyceride concentration. No changes in Meteorin-like were observed throughout trials. These findings suggest that an increase in RMR occurs following a single resting hypoxic exposure and independently to Meteorin-like protein. The fourth study observed reductions in body mass (-2.36 ± 1.41 kg) and increases in CHO oxidation during an altitude stay in Peru (18 days, 3400 m) (n=10; five females, five males). The reduction in body mass (-1.89 ± 1.31 kg) was sustained four weeks post-return to sea-level. Salt, sweet and bitter taste sensations were reduced at 3,400 m compared to sea-level. No changes in self-reported appetite were observed throughout the testing period. Furthermore no changes in circulating Meteorin-like protein were observed upon return to sea-level at one and four weeks post-altitude stay. Study five investigated the blood lipid response to a high lipid meal consumed one and four weeks post-return to sea-level following an altitude stay (18 days, 3400 m) (n=10; five females, five males). No lasting postprandial effects were observed. It is likely that a time dependent effect of hypoxia exists with regards to postprandial blood lipid responses. Taken together acute and intermediate exposure to hypoxic conditions alter substrate oxidation with the potential to induce losses in body mass, independently to changes in Meteorin-like protein and self-reported appetite. Specifically, prolonged stay at moderate altitude results in a greater dependency on CHO use. Increases in RMR were observed during an acute severe bout of hypoxia, although this was not a consistent effect throughout prolonged exposure and should be further investigated. Altered taste during an altitude stay may influence food preferences, energy intake and subsequent changes in body mass and should be considered an area of future investigation. Higher circulating levels of FFA and TAG, demonstrates a metabolic perturbation from a single, acute severe hypoxic exposure.

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Parry, Sion A. "Metabolic responses to short-term high-fat overfeeding". Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/26916.

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The main aim of this thesis was to increase our understanding of the metabolic responses associated with short-term high-fat overfeeding. To this end, four separate studies are described in this thesis; each of which involved the provision of a high-fat, high-energy diet to young, healthy, lean individuals. The first of these experimental chapters (Chapter 2) determined the effects of a 7-day, high-fat (65%), high-energy (+50%) diet on postprandial metabolic and endocrine responses to a mixed meal challenge. This chapter demonstrates that 7-days of overfeeding impaired glycaemic control in our subject cohort but did not influence the response of selected gut hormones (acylated ghrelin, GLP-1 and GIP). In a mechanistic follow up study utilising stable isotope tracer methodology we then demonstrate that overfeeding-induced impairments in glycaemic control are attributable to subtle alterations in plasma glucose flux, rather than the overt tissue-specific adaptations (e.g. increased EGP, or reduced glucose disposal) that have previously been reported (Chapter 3). In an attempt to delineate the time-course of diet-induced impairments in glycaemic control, we then investigated the effects of 1-day of overfeeding (+80% energy with 73% of total energy coming as fat) (Chapter 4). Results demonstrate that a single day of overfeeding elicits responses which are comparable to 7-days of high-fat overfeeding; highlighting the rapidity with which excessive high-fat food intake can negatively influence glucose metabolism. In chapter 5 we utilised stable isotope tracer and muscle biopsy techniques to demonstrate that 7-days of high-fat overfeeding impairs glycaemic control but does not influence the fed-state mixed muscle protein fractional synthesis rate (FSR). In conclusion, the findings of this thesis demonstrate that while short-term high-fat overfeeding negatively influences whole-body glucose metabolism, skeletal muscle protein metabolism appears to be relatively unaffected in young, lean, healthy humans.

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11

Granfeldt, Yvonne. "Food factors affecting metabolic responses to cereal products". Lund : Dept. of Applied Nutrition and Food Chemistry, Lund University, 1994. http://catalog.hathitrust.org/api/volumes/oclc/39774219.html.

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Goran, M. I. "Metabolic responses to chronic endotoxin infusion in the rat". Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376584.

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Iredahl, Fredrik. "Assessment of microvascular and metabolic responses in the skin". Doctoral thesis, Linköpings universitet, Avdelningen för kliniska vetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-132167.

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The general aim of this project was to develop experimental in vivo models that allow for minimally invasive investigations of responses in the skin to microvascular and metabolic provocations. The cutaneous microvasculature has emerged as a valuable model and been proposed to mirror the microcirculation in other organs. Dysfunction in the cutaneous microcirculation has thus been linked to systemic diseases such as hypertension and diabetes mellitus. Models for investigating skin responses could facilitate the understanding of pathophysiological mechanisms as well as effects of drugs. In the first study, three optical measurement techniques (laser Doppler flowmetry (LDF), laser speckle contrast imaging (LSCI) and tissue viability imaging (TiVi)) were compared against each other and showed differences in their ability to detect microvascular responses to provocations in the skin. TiVi was found more sensitive for measurement of noradrenaline-induced vasoconstriction, while LSCI was more sensitive for measurement of vascular occlusion. In the second study, microvascular responses in the skin to iontophoresis of vasoactive drugs were found to depend on the drug delivery protocol. Perfusion half-life was defined and used to describe the decay in the microvascular response to a drug after iontophoresis. In the third study, the role of nitric oxide (NO) was assessed during iontophoresis of insulin. The results showed a NO-dependent vasodilation in the skin by insulin. In the fourth study the vasoactive and metabolic effects of insulin were studied after both local and endogenous administration. Local delivery of insulin increased skin blood flow, paralleled by increased skin concentrations of interstitial pyruvate and lactate, although no change in glucose concentration was observed. An oral glucose load resulted in an increased insulin concentration in the skin paralleled by an increase in blood flow, as measured using the microdialysis urea clearance technique, although no changes in perfusion was measured by LSCI. The thesis concludes that when studying skin microvascular responses, the choice of measurement technique and the drug delivery protocol has an impact on the measurement results, and should therefore be carefully considered. The thesis also concludes that insulin has metabolic and vasodilatory effects in the skin both when administered locally and as an endogenous response to an oral glucose load. The vasodilatory effect of insulin in the skin is mediated by nitric oxide.

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Midgley, Nicola-Ann. "Metabolic responses in melanoma cells to combined nutrient supplementation". Thesis, Rhodes University, 1997. http://hdl.handle.net/10962/d1004096.

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This thesis examined the effect and biochemical mechanism by which combined vitamin E and C supplementation may influence tumour cell growth. The study initially addressed the effect of combined vitamin E succinate and Asc supplementation over a nutritional concentration range (5- 20μg/ml) and (25-50μg/ml) respectively, on the in vitro growth of non-malignant LLCMK and malignant BL6 cells. Supplementation of BL6 and LLCMK cells with combined vitamin E succinate and ascorbic acid, resulted in no significant increasing or decreasing trend in LLCMK cell growth, while in BL6 cells a significant decrease in cell growth was observed at all combined vitamin concentrations. It has been suggested that these vitamins may act synergistically to inhibit tumour cell growth through their antioxidant properties in quenching free radicals and lipid peroxidation and furthermore through their modulation of the activities of various enzymes and metabolites in the eicosanoid pathway. This study consequently investigated the effects of combined vitamin E succinate and ascorbic acid supplementation on these parameters. Throughout this study, emphasis was placed on the BL6 melanoma cells, as combined vitamin E succinate and ascorbic acid supplementation did not significantly affect growth or levels of secondary metabolites in the non-malignant LLCMK cells. Combined vitamin E succinate and ascorbic acid supplementation of BL6 cells resulted in a marked but non significant increase in free radical and a significant increase in lipid peroxidation levels. This prooxidant effect was accompanied by a significant decrease in BL6 cell growth, suggesting that the growth inhibitory effects of combined vitainin E succinate and ascorbic acid on BL6 cells in vitro was not mediated through their synergistic antioxidant properties. Vitamin E succinate is a nonphysiological antioxidant in its esterified form, hence cleavage of the succinate group must occur in order for ascorbic acid to interact with the free alcohol, vitamin E. The inability of combined vitamin E succinate and ascorbic acid to reduce free radicals and lipid peroxidation levels within BL6 cells may not be due to their ineffectiveness as antioxidants but rather the presence of other contributing factors which influence the oxidation state within the BL6 cells. Vitamin E is believed to modulate membrane-bound enzymes through membrane stabilization. Furthermore, the stabilizing effect of vitamin E may be enhanced by the ascorbic acid-sparing effect of vitamin E. Hence, this study investigated the effect of combined vitamin E succinate and ascorbic acid in modulating the activity of various enzymes and secondary messengers in the eicosanoid pathway. Supplementation with combined vitamin E succinate (5-20μg/ml) and ascorbic acid (25-50μg/ml) resulted in significant increases in phospholipase A₂, 5-lipoxygenase, cyclooxygenase and adenyl ate cyclase activity, with a significant decrease in BL6 cell growth. The possible synergistic action of these vitamins in terms of modulating membrane-bound enzymes was further substantiated by uptake and cellular distribution studies. Vitamin E succinate and vitamin E in the membrane fraction increased significantly compared to control cultures, while ascorbic acid levels were significantly higher in the stroma fraction when compared to membrane fractions. Consequently, another factor accounting for increased activities of phospholipase A2, 5-lipoxygenase and adenylate cyclase activities as a result of vitamin supplementation in BL6 cells may be an increased availability of Ca²+. Supplementation of BL6 cells with combined vitamin E succinate and ascorbic acid resulted in significant increases in intracellular Ca²+ levels at all combined vitamin groups. Furthermore, this increase in intracellular Ca²+ was positively correlated with cl1anges of the above-mentioned enzyme activities. Within the eicosanoid pathway, the rate of prostaglandin synthesis is regulated by phospholipase A₂ activity and arachidonic acid release, and the net prostaglandin production is dependent on cyclooxygenase activity, hence the effects of combined vitamin E succinate and ascorbic acid on arachidonic acid composition and prostaglandin production within BL6 cells was determined. The percentage arachidonic acid composition of the BL6 cells was elevated and inversely related to cell growth following combined vitamin E succinate and ascorbic acid supplementation. Prostaglandin E₂ and prostaglandin I₂ levels increased significantly, while those of prostaglandin D2 and prostaglandin F₂α increased markedly following supplementation of combined vitamin E succinate and ascorbic acid. These increases in prostaglandin levels were inversely related to BL6 cell growth, suggesting that the prostaglandins were involved in negative regulation of BL6 cell growth. When comparing the levels of prostaglandins, prostaglandin E2 levels were significantly higher when compared to prostaglandin D₂, prostaglandin F₂α and prostaglandin I₂ suggesting that vitamin E₂ succinate and ascorbic acid effects were mediated primarily through an increase in prostaglandin E2. Hence, prostaglandin E2 levels in combined vitamin E succinate and ascorbic acid appeared to be dependent on the amount of precursor present and the activity of its synthetic enzymes. This was confirmed when BL6 cells were supplemented with arachidonic acid. Arachidonic acid had an inhibitory effect on BL6 cell growth and also stimulated prostaglandin E₂ production. Prostaglandin E₂ levels are in turn believed to modulate adenylate cyclase activity in BL6 cells, hence it is reasonable to conclude that adenylate cyclase activity is dependent on prostaglandin E₂ levels. Combined vitamin E succinate and Asc supplementation to BL6 cells resulted in significant increases in adenyl ate cyclase and cyclic adenosine monophosphate, which again correlated with a significant decrease in cell growth. As cyclic adenosine monophosphate has a regulatory role in the cell cycle this study suggested that the effect of combined vitamin E succinate and ascorbic acid supplementation was mediated through the final effect provided by the second messenger, cyclic adenosine monophosphate. This was confirmed when BL6 cells were supplemented with dexamethasone, a phospholipase A₂ inhibitor. This treatment rsulted in combined vitamin E succinate and ascorbic acid having no inhibitory effect on BL6 cell growth. Cyclooxygenase activity, prostaglandin E₂ levels, adenylate cyclase activity and cyclic adenosine monophosphate levels were significantly lower in dexamethasone-treated cells compared to non-treated dexamethasone cultures. The reason for the increased free radical and lipid peroxidation levels in BL6 cells was further investigated. Cyclooxygenase enzymes are believed to generate free radical species during catalytic activity. Analysis of free radical and lipid peroxidation levels following supplementation with dexamethasone revealed markedly lower free radical and significantly lower lipid peroxidation levels in comparison with control cultures and non dexamethasone-treated cultures. These results suggest that the observed increases in free radical and lipid peroxidation levels in BL6 cells supplemented with combined vitamin E succinate and ascorbic acid were indirectly due to the increase in cyclooxygenase activity in these cells.

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15

Ribeiro, David. "Hormonal and metabolic responses in simulated and real shift work". Thesis, University of Surrey, 1999. http://epubs.surrey.ac.uk/843353/.

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Coronary Heart Disease (CETO) is one of the most common causes of mortality in industrialised societies, and it has been demonstrated elsewhere that shift workers have an increased risk of developing CHD compared to day-workers. One possible explanation for this increased risk is that a shift worker may show inappropriate postprandial responses to a night-time meal, when their biological clock is not adapted to the night shift. This could lead to an elevation in the circulating levels of certain hormones and metabolites, such as triacylglycerol (TAG) and insulin, which are known to be risk factors for CHD. This thesis investigated the relationships between meal times and postprandial hormone and metabolic responses in simulated and real-life shift-workers. The work is presented as three major clinical trials. In the first of these, a combination of timed bright light and darkness/sleep was used to induce a gradual 9-hour phase advance in 12 healthy subjects, who then underwent a rapid 9-hour phase delay. Three meal study days were arranged, to occur during the baseline condition, immediately after the rapid phase delay, so that the subjects effectively had "simulated jet lag", and two days later. Blood parameters measured included plasma glucose, insulin, proinsulin, C-peptide, non-esterified fatty acids (NEFA), TAG and glucose- dependent insulinotropic polypeptide (GIP). Substantial differences in plasma TAG and NEFA were observed in the postprandial responses when the subjects consumed an identical meal immediately after the rapid phase delay, compared with during the baseline conditions. Two days after the rapid phase delay, subjects showed inteimediate hormone and metabolite levels, suggesting that the biological clock had a major effect on these postprandial responses. In the second study, day and night-time postprandial responses were compared in a simulated shift work environment, and the effectiveness of a number of potentially beneficial procedures was investigated. These included alterations to the content of the meal consiraied prior to the night shift, bright light exposure during the night shift, and a daytime rest period prior to the night shift. As in the first study, significant differences were seen in a number of hormones and metabolites on the night shift. compared with during the day. The content of the previous meal, bright light exposure and a daytime rest period prior to the night shift all had significant effects on the night-time postprandial responses. The most exciting discovery made was that a single 8-hour night-time bright light exposure significantly lowered the TAG postprandial responses on the simulated night shift. As all the work conducted up until this point had utilised simulated conditions, it was important to illustrate that similar differences in postprandial responses at night-time could be demonstrated in "real-life shift workers". Thus, nine midwives were recruited from the Royal Surrey County Hospital, and studied on four occasions. This allowed comparison of postprandial responses on both day and night shifts, and also allowed further investigation of the effect of altering the content of the previous meal. Significant differences were again found in a number of blood parameters when the night-time and day-time responses to the test meal were compared, with the most striking being a delayed NEFA rise on the night shift, compared with during the day. In conclusion, this series of studies have illustrated that the human body responds differently to a meal consumed at night-time, compared with during the day, both in a simulated and a real-life environment. This results in variations in the levels of a number of known CHD risk factors, and may be linked with the elevated CHD risk reported in shift workers. Alteration to the meal prior to the night shift, exposure to bright light during the night shift, and instituting a rest period prior to the night shift, were all shown to be potentially beneficial in reducing the variation between day and night-time responses.

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16

Beech, Adam. "Metabolic profiling analysis of pharmacodynamic responses to chemotherapy in cancer". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/51548.

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Cancer is one of the leading causes of death worldwide, and various chemotherapeutic agents are in use for its treatment. However, response to these therapies is generally low and resistance to these drugs is a daunting problem for cancer intervention. Prediction of response to drug treatment and the pharmacodynamics of response following treatment are important avenues for research into the clinical efficacy of chemical interventions in cancer, and in the goal of personalisation of medicine through patient stratification. This research project investigated potential pharmacodynamic biomarkers of response to anticancer drugs through metabonomics, assessing molecular changes in metabolic profile following specific drug treatments. Ultra-performance liquid chromatography-mass spectrometry was used in an untargeted approach on in vitro and in vivo sample sets. Multivariate modelling and statistics were employed alongside database interrogation to identify potential metabonomic biomarkers of response to treatment in three studies: in vitro treatment of breast cancer cells with histone methyltransferase inhibitors; in vitro and in vivo investigation of epidermal growth factor receptor inhibition in colorectal cancer; and in vivo assessment of platinum resensitisation using AKT inhibition in ovarian cancer. Across the three studies compositional changes in the abundance of several lipids based on treatment was seen, with several phosphatidylcholines, sphingomyelins and ceramides consistently found to increase in concentration in cells or patients that responded to therapy. Polar metabolites that were found to change in level as a result of treatment were more specific to each study. Each tentative identification represents a potential biomarker of treatment response, and requires ID confirmation with chemical standards and fragmentation before further investigating further. The trajectory of the results points to the feasibility of metabonomic biomarkers in early clinical trials as pharmacodynamic and response biomarkers that have the potential to optimise therapy for each cancer patient.

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Cannell, Elizabeth. "Neuroendocrine and metabolic responses to desiccation stress in Drosophila melanogaster". Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/7120/.

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Insects are highly successful and their large numbers lead to economic loss through crop damage and disease transmission. Insecticides provide a valuable tool for control of insect populations. However, as resistance is increasing to existing products, new modes of action are required for the development of novel products. Understanding of the biological mechanisms underlying stress resistance in insects may provide insight into new potential insecticide targets. Malpighian tubules are critical for epithelial fluid transport and xenobiotic tolerance in insects. The function of Malpighian tubules in desiccation stress tolerance was explored by examining changes in gene expression, protein levels, fluid transport rates, and metabolism following stress exposure. The results indicate a reduction in secretion rate during desiccation that is reflected in accumulation of metabolites that are normally processed and excreted by the tubules. Moreover, the involvement of Drosophila melanogaster diuretic hormones corticotrophin releasing factor-like (DH44) and leucokinin (LK) were examined using genetic manipulations based on the GAL4-UAS system. Highly selective manipulation of the DH44-producing neurons via knockdown of DH44 and neuronal ablation indicates that suppression of DH44 signalling contributes to desiccation tolerance. This result is supported by the finding that knockdown of DH44 receptor 2 in the Malpighian tubule principal cells improves survival during desiccation stress. Previous work suggests the possibility of interaction between LK and DH44 signalling as LK receptor (LKR) is colocalised to the DH44 neurons. This hypothesis is supported by the results of this study as selective knockdown of LKR and DH44 in the DH44 neurons produced opposing effects on desiccation tolerance. Moreover, knockdown of DH44 in the DH44 neurons or ablation of these neurons resulted in significantly decreased LKR expression in the Malpighian tubules. Finally, a novel role for the Malpighian tubules in starvation tolerance was uncovered by the study, with LKR gene expression increasing significantly following starvation. Knockdowns of either DH44-R2 or LKR in the Malpighian tubules significantly impaired starvation tolerance. Here, a mechanism for this role of renal epithelia in starvation tolerance is proposed.

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Ratcliff, Lance Huggins Kevin W. "Resting metabolism and metabolic responses to solid and liquid meals in sedentary and exercising college-age males". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Nutrition_and_Food_Science/Dissertation/Ratcliff_Lance_45.pdf.

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Brugnara, Laura. "Metabolic responses to physical activity in subjects with type 1 diabetes". Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/396156.

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Type 1 diabetes mellitus is an autoimmune chronic disease that has undergone drastic changes on its clinical natural history in the last decades. Until the early XX century, the diagnosis of diabetes would mean a fatal outcome in few weeks or months. The evidence of hyperglycemia associated with abrupt polyuria, polydipsia, polyphagia and weight loss in a child or a young person determined a diagnosis of failure of insulin secretion, metabolic catabolism and death. The introduction of treatments with exogenous insulin was the first important change in the natural clinical history of diabetes. Subjects affected by diabetes experienced then a hope of treatment and life. The main initial concern of physicians and scientists was to avoid important episodes of hypo or hyperglycemia, which could lead to hypoglycemic coma or diabetic ketoacidosis. Different classes of insulins were tested and used with success, offering better life expectancy for the affected persons. In parallel with the provided increase of life expectancy, chronic complications related to diabetes were prone to appear. Those patients who, at that moment, benefit from the exogenous insulin, but maintained many episodes of hyperglycemia and glycemia fluctuations, developed chronic complications leading to blindness, renal failure, limbs amputations and/or cardiovascular complications as heart attack or stroke. Aware of the consequences of hyperglycemia, researchers started to design studies promoting a more strict control of glucose levels, with the intention of minimizing chronic complications related to diabetes. Studies for type 1 diabetes (T1D) like DCCT, published in 1993 (The Diabetes Control and Complications Trial Research Group, 1993) and its follow-up EDIC (Nathan et al., 2005), and others alike for type 2 diabetes (T2D) (UK Prospective Diabetes Study, UKPDS Group 1998), proved the reduction of complications rates and marked a new change in the natural clinical history of diabetes. Recently, tighter glycemic control became possible with the help of new insulins, insulin infusers, glucose sensors and nutrition research. The incidence of retinopathy, nephropathy, neuropathy and their consequent serious outcomes as blindness, end renal stage disease and lower limb amputations, reduced in the past two decades, as described in the US patients with diabetes (Gregg et al., 2014). The excess risk of mortality in individuals over 20 years old with diabetes (T1D and T2D) if compared with the risk of individuals without diabetes has decreased over time in both Canada and the UK, as shown in data recently published (M Lind et al., 2013). This may be, in part, due to the earlier diagnosis, as well as to improvements in diabetes care (M Lind et al., 2013). In patients with T1D, a reduction of all-cause mortality and also of specific cardiovascular mortality could be verified, especially if associated with a good glycemic control; these rates, nevertheless, are still the double of the ones seen in subjects without diabetes (Marcus Lind et al., 2014). Physical activity is considered as a health promoter procedure for general population and a therapeutic tool for prevention and/or treatment of several chronic diseases, like T2D, cardiovascular disease or cancer. Persons with T1D are stimulated to participate in exercise training programs and competition events. Nowadays, with the current knowledge, several elite athletes with T1D are able to compete in the same categories that the ones without diabetes, but requiring for that a strict balance among insulin adjustments, carbohydrate intake and physical activity characteristics. Many questions may be formulated at the present time: are persons with T1D being beneficiated from physical activity as persons without diabetes? Do the subjects with T1D present the same physical conditions for exercise performance than the non-diabetic ones? Do they present different metabolic response when performing a session of exercise? Does physical activity improve lipoprotein profile generating cardiovascular benefits for the subjects with T1D? What are the characteristics of muscular composition of patients with T1D, and are they different from subjects without diabetes? What are the factors that could be interfering? These questions are discussed in the present thesis. Some answers were achieved and some other questions emerged. Nowadays, the availability of new technological approaches, the improvements on basic research, and the possibility to integrate the information of basic research with clinical research are improving the knowledge in biomedical science. A better understanding of physiopathology can be obtained, and with it, a better care, a better quality of life, and longer life expectancy can be offered to persons who have type 1 diabetes.

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Marvar, Paul J. "Effect of high salt intake on arteriolar responses to metabolic stimuli". Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4696.

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Thesis (Ph. D.)--West Virginia University, 2006.
Title from document title page. Document formatted into pages; contains xiv, 197 p. : ill. Vita. Includes abstract. Includes bibliographical references.

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Glund, Stephan. "Molecular mechanisms governing contraction-induced metabolic responses and skeletal muscle reprogramming /". Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-436-5/.

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Ovington, K. S. "Physiological and metabolic responses of the rat to Nippostrongylus brasiliensis infection". Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332636.

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23

Allerton, Dean. "Postprandial metabolic and appetite responses following whey protein supplementation at breakfast". Thesis, Northumbria University, 2016. http://nrl.northumbria.ac.uk/31600/.

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The prevailing lifestyle pattern in western society results in humans spending the majority of non-sleeping hours in the postprandial state. Given that impaired postprandial metabolism may have adverse consequences for health, interventions that positively influence the postprandial milieu are pertinent considering the global rise in prevalence of chronic metabolic disorders. The aim of this thesis was to investigate whether consumption of whey protein, which has reported beneficial properties relevant to metabolic health, could impact favourably upon acute and second-meal postprandial metabolic and appetite responses. More specifically, a series of studies was designed to establish the conditions under which a rationale for whey protein supplementation may be strongest, through investigation of co-ingestion with other macronutrients, timing of supplementation and interactions with low-moderate intensity exercise. Study one revealed that consuming whey (20 g) alongside a high-carbohydrate or high-fat breakfast significantly augmented the plasma insulin response to that meal in physically active, normal-weight males, without significantly affecting postprandial glycaemia, lipaemia or subjective appetite. Whey protein consumption at breakfast did not affect second meal responses or 24-hour glycaemia when co-ingested with either macronutrient. Study two compared the effects of the same dose of protein administered before, during or after a mixed-macronutrient breakfast in centrally-obese males. Consuming whey as a preload 15 minutes prior to breakfast significantly reduced postprandial glycaemia compared to consuming it afterwards or not at all, with evidence indicating that insulin-independent mechanisms may be responsible. Again, prior whey consumption, irrespective of timing, did not influence glycaemic, insulinaemic or appetite profiles following a standard lunch meal. The final study investigated the effects of a post-exercise whey protein preload on postprandial metabolism and appetite in physically inactive, centrally-obese males. Postprandial glycaemia was moderately impaired following brisk walking exercise without supplemental protein, however this effect was negated when exercise was followed by a whey preload, with a reduced peak glycaemic excursion observed compared to other conditions. Ad libitum energy intake, assessed at lunch, did not differ between conditions. This thesis has shown that whey protein supplementation at breakfast may acutely influence postprandial glycaemia in centrally-obese individuals, however this beneficial effect is not carried over to subsequent meal occasions. Timing of protein intake appears to be important, and this effect is not diminished by prior walking exercise in previously sedentary individuals. Further studies to investigate the effects of whey protein supplementation at multiple meals are required to determine whether this may be a worthwhile strategy to prevent day-long elevated glycaemic exposure.

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Palmer, Gary Stanley. "Physiological and metabolic responses to constant and variable load cycling performance". Doctoral thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/26920.

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The experiments described in this thesis comprise a series of related, yet independent investigations examining the physiological and metabolic responses of well-trained amateur cyclists under conditions designed to mimic actual competitive situations, during individual and mass start races. In Section A the physiological responses to constant load and steady state exercise are determined. In Section B, the metabolic factors associated with constant and variable load cycling performance are examined.

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Newell, Michael L. "Metabolic, neuromuscular, and performance responses to graded carbohydrate ingestion during exercise". Thesis, University of Stirling, 2015. http://hdl.handle.net/1893/22397.

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A dose response relationship between carbohydrate (CHO) ingestion and exercise performance has not been consistently reported. Additionally the underlying metabolic and neuromuscular explanations for an improvement in performance with increasing doses of CHO have not been fully explained. In Chapter 2 of this thesis 20 male cyclists completed 2 h of submaximal exercise followed by a time trial task (531 ± 48KJ). Three CHO electrolyte beverages, plus a control (water), were administered during a 2 h ride providing 0, 20, 39 or 64 g CHO·h-1 at a fluid intake rate of 1 L·h-1. Performance was assessed by time to complete the time trial task, mean power output sustained, and pacing strategy used. Mean task completion time (min:sec ± SD) for 39 g·h-1 (34:19.5 ± 03:07.1, p=0.006) and 64 g·h-1 (34:11.3 ± 03:08.5 p=0.004) of CHO were significantly faster than control (37:01.9 ± 05:35.0). The mean percentage improvement from control was -6.1% (95% CI: -11.3 to -1.0) and -6.5% (95% CI: -11.7 to -1.4) in the 39 and 64 g·h-1 trials respectively. The 20 g·h-1 (35:17.6 ± 04:16.3) treatment did not reach statistical significance compared to control (p = 0.126) despite a mean improvement of -3.7% (95% CI -8.8 to 1.5%). These data demonstrate that consuming CHO at a rate between 39 to 64 g·h-1 is likely to be optimal for most individuals looking to utilise a single source CHO as an ergogenic aid during endurance performances lasting less than 3 hrs. Attempts have been made to try and understand the acute metabolic regulation that occurs when ingesting increasing amounts of CHO. However, no one study has fully investigated the metabolic mechanisms underlying graded increments of CHO ingestion. In Chapter 3 we aimed to utilise stable isotopes and blood metabolite profiles to examine the integrated physiological responses to CHO ingestion when ingested at rates throughout the range where performance gains appear greatest. Twenty well-trained male cyclists completed 2 h constant load ride (95% lactate threshold, 185 ± 25W) where one of three CHO beverages, or a control (water), were administered every 15 min, providing participants with 0, 20, 39 or 64 g CHO·h-1 at a fixed fluid intake rate of 1L·h-1. Dual glucose tracer techniques (6,6,2H2 glucose and U13C labelled glucose) were used to determine glucose kinetics and exogenous carbohydrate oxidation (EXO) during exercise. Endogenous CHO contribution was suppressed in the second hour of exercise when consuming 39 and 64 g·h-1 in comparison to 0 g·h-1 (-7.3%, 95%CI: -13.1 to -1.6 and -11.2%, 95%CI: -16.9 to -5.5 respectively). Additionally, consuming 64 g·h-1 suppressed the endogenous CHO contribution by -7.2% (95%CI: -1.5 to -13.0) compared to the 20 g·h-1 treatment. Exogenous CHO oxidation rate increased by 0.13 g·min-1 (95%CI: 0.10 to 0.15) and 0.29 g·min-1 (95%CI: 0.27 to 0.31) when consuming 39 and 64 g·h-1 in comparison to 20 g·h-1 of CHO. Peak exogenous CHO oxidation rates were 0.34 (0.06), 0.54 (0.09) and 0.78 (0.19) g·min-1 for 20, 39 and 64 g·h-1 respectively. Plasma NEFA concentration was 0.10 (95%CI: 0.07 to 0.13), 0.12 (95%CI: 0.10 to 0.16) and 0.16 (95%CI: 0.13 to 0.19) mmol.L-1 higher when consuming 0 g·h-1 in comparison to 20, 39 and 64 g·h-1 respectively. Both 39 and 64 g·h-1 were effective at sparing endogenous CHO stores of which it is estimated that most of this is liver glycogen sparing, but the measured response was highly variable between individuals. Consuming 39 g·h-1 of CHO appears to be the minimum ingestion rate required to have a significant metabolic effect that results in an increase in performance. Recent research has indicated a key role of endogenous CHO sensing and oral glucose sensing in maintaining central drive and peripheral function during endurance exercise tasks. Consuming 39 and 64 g·h-1 of CHO elicits the greatest improvements in performance and also demonstrate a similar metabolic response. The improvement in subsequent time trial performance when consuming 39 and 64 g·h-1 coincided with significant alterations in whole body substrate usage that lead to endogenous CHO sparing at the same ingestion rates. In Chapter 4 we aimed to utilise gold standard neuromuscular function assessment techniques, alongside novel measures, to investigate the effect of consuming different rates of CHO on neuromuscular function during and following prolonged cycling exercise. In a double-blind, randomised cross-over design, well-trained male cyclists (n=20, mean±SD, age 34 ± 10 y, mass 75.8 ± 9 kg, peak power output 394 ± 36 W, V̇O2max 62 ± 9 ml·kg-1·min-1) completed 2 familiarisation trials then 4 experimental trials. Trials involved a 2 h submaximal ride followed by a high intensity time trial task lasting approx. 35 min with each of 0, 20, 39 and 64 g·h-1 CHO ingestion rates during submaximal exercise. Each trial involved pre and post exercise assessments (MVC, Mwave twitch potentiation and force, motor unit recruitment and firing rate assessment using high density EMG) and during exercise (gross EMG amplitude). MVC peak torque values were reduced post exercise by -20.4 nM (95%CI: -26.5 to -14.4) in comparison to pre value on all trials with no differences between trials. The firing rates of early recruited motor units significantly increased by 1.55 pps (95%CI: 0.51 to 2.59) following exercise in comparison to pre-exercise rates. Gross EMG during the 2 h cycling bout revealed a main effect of treatment (p<0.01) but post hoc comparisons provided no clarity and likely reflect methodological issues. Consuming CHO at ingestion rates between 20 and 64 g·h-1 had little to no impact on the neuromuscular function of well-trained cyclists when comparing pre and post fatiguing exercise values. Despite differences in time trial completion time between trials, following exercise to fatigue in an endurance task, no post exercise differences were detected.

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26

Hamada, Taku. "Neuromuscular and metabolic responses to electrical stimulation of human skeletal muscle". Kyoto University, 2004. http://hdl.handle.net/2433/147700.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(人間・環境学)
甲第10941号
人博第228号
15||183(吉田南総合図書館)
新制||人||57(附属図書館)
UT51-2004-G788
京都大学大学院人間・環境学研究科文化・地域環境学専攻
(主査)教授森谷敏夫, 教授津田謹輔, 助教授小田伸午
学位規則第4条第1項該当

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27

Kopa, Dawn Elizabeth. "Sex differences in the cardiovascular and metabolic responses to leptin infusion". Tallahassee, Fla. : Florida State University, 2009. http://purl.fcla.edu/fsu/lib/digcoll/undergraduate/honors-theses/244562.

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Thesis (Honors paper)--Florida State University, 2009.
Advisor: Dr. J. Michael Overton, Florida State University, College of Arts and Sciences, Dept. of Biology. Includes bibliographical references.

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De, Jaham Clémence. "Metabolic responses of early developing sugar beet plant to heat stress". Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0730.

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La betterave sucrière est la deuxième plante en termes de production de sucre avec 19,6% du sucre produit dans le monde entre 2015 et 2016, derrière la canne à sucre. Cultivée dans les zones tempérées comme le nord de la France et la Belgique, elle est sensible au stress thermique modéré. En effet, une augmentation de 1°C de la température moyenne entraîne une perte de rendement de 29%. Dans le cadre du réchauffement climatique et afin de fournir aux agriculteurs des variétés ayant une meilleure résistance à la chaleur, la compréhension des réponses de la betterave sucrière au stress hyperthermique est nécessaire. Pour cela, une étude des réponses physiologiques et métaboliques a été effectuée avec trois hybrides : un hybride de type sucré avec 18% de sucre dans sa racine, un hybride de type lourd avec un meilleur rendement que la moyenne mais avec seulement 17% de sucre dans sa racine, et un hybride dit « résistant » au stress hyperthermique, ayant le meilleur rendement aux champs avec des températures plus élevées. Alors que la photosynthèse nette n’était pas modifiée en condition de stress, une croissance plus rapide de la rosette a été observée aux stades jeunes pour les trois hybrides. Une approche de modélisation suggère qu’une croissance de la rosette plus rapide contrecarre les effets du stress hyperthermique sur la production racinaire. Cette hypothèse est confirmée par le fait que l’hybride le plus performant a la croissance foliaire la plus rapide. Le stress hyperthermique provoque une forte diminution du stockage transitoire du carbone dans les feuilles matures. Dans les feuilles en cours de développement, le stockage transitoire du carbone, dont la moitié sous forme d’amidon, était seulement maintenu chez l’hybride le plus performant. Un calcul intégrant les besoins en carbone de la croissance foliaire suggère que ce maintien contribue significativement au maintien du rendement chez cet hybride. Par ailleurs, un marqueur putatif de la sensibilité au stress hyperthermique a été identifié lors de cette étude. Au final ce travail a permis de mieux comprendre comment la betterave sucrière répond à l’élévation de la température et ainsi proposer de nouvelles stratégies pour l’amélioration de cette espèce
Sugar beet is the second largest sugar-producing crop, with 19.6% of the sugar produced in the world between 2015 and 2016, behind sugarcane. Cultivated in temperate zones like the north of France and Belgium, it is sensitive to moderate thermal stress. Indeed, an increase of 1°C in the average temperature leads to a loss of efficiency of 29%. In the context of global warming and in order to provide farmers with varieties with better resistance to heat, an understanding of sugar beet responses to hyperthermic stress is necessary. For this, a study of physiological and metabolic responses was carried out with three hybrids: a sweet-type hybrid with 18% sugar in the root, a heavy-type hybrid with a better yield than average but with only 17% sugar in the root, and a so-called "resistant" hybrid, which has the best yield at higher temperatures. While net photosynthesis was not altered in stress conditions, more rapid growth of the rosette was observed at the young stages for all three hybrids. A modeling approach suggests that faster rosette growth counteracts the effects of hyperthermic stress on root production. This hypothesis was confirmed by the fact that the best performing hybrid had the fastest shoot growth. Hyperthermic stress caused a significant decrease in transient carbon storage in mature leaves. In developing leaves, transient storage of carbon, half as starch, was only maintained in the best performing hybrid. A calculation incorporating the carbon requirement of foliar growth suggests that this maintenance contributes significantly to the maintenance of yield in this hybrid. In addition, a putative marker of hyperthermic stress sensitivity was identified in this study. In the end, this work provides a better understanding of how sugar beet responds to the rise in temperature, thus proposing new strategies for the improvement of this species

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Toda, Kaoru, Yoshiharu Oshida, Mizuho Tokudome, Tomoko Manzai i Yuzo Sato. "Effects on moderate exercise on metabolic responses and respiratory exchange ratio (RER)". Nagoya University School of Medicine, 2002. http://hdl.handle.net/2237/5383.

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30

Cheetham, Mary E. "Effect of training on the metabolic responses to treadmill sprinting in man". Thesis, Loughborough University, 1987. https://dspace.lboro.ac.uk/2134/33031.

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Whilst the metabolic responses to submaximal exercise have been relatively well documented little information is available relating to maximal exercise. Thus, the purpose of this study was to examine the physiological and metabolic responses to sprint running exercise, with the objective being to contribute to both the understanding of those factors which underlie or determine performance and also to the current understanding of intermediate metabolism in man during exercise. A laboratory-based running test was developed using a non-motorised treadmill, which allowed the simultaneous examination of performance and the associated changes in muscle metabolism during sprint exercise. This test was sensitive enough to monitor the differences in performance between individuals with varying training backgrounds and to monitor the changes in performance within the same group of individuals resulting from a short period of training.

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31

Kenéz, Ákos [Verfasser]. "Metabolic responses of adipose tissue in the periparturient dairy cow / Ákos Kenéz". Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2015. http://d-nb.info/1073881598/34.

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32

Luna, Stelio Pacca Loureiro. "Equine opioid, endocrine and metabolic responses to anaesthesia, exercise, transport and acupuncture". Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309155.

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Fletcher, A. J. W. "Glucocorticoids and acute hypoxaemia in fetal sheep : cardiovascular, endocrine and metabolic responses". Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599082.

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These studies have investigated the effects of fetal treatment with dexamethasone on the fetal cardiovascular, endocrine and metabolic responses to a 1h episode of acute hypoxaemia occurring both during, and 48 h following, the period of dexamethasone treatment in fetal sheep at 0.8 of gestation. Parallels have been drawn with the normal maturation of the cardiovascular, endocrine and metabolic responses to acute hypoxaemia by investigating developmental changes in the patterns of these responses close to term, and correlating them with the preparturient increase in fetal plasma glucocorticoid concentration. Mechanisms mediating the changes in the cardiovascular responses to acute hypoxaemia in the dexamethasone-treated and late gestation fetuses have been addressed by measuring the associated changes in fetal plasma concentrations of vasoconstrictor hormones (noradrenaline, adrenaline, arginine vasopressin, angiotensin II and neuropeptide Y), hormones associated with the hypothalamo-pituitary-adrenal axis (ACTH and cortisol), by assessing changes in the pressor and vasopressor responses to exogenous bolus doses of phenylephrine, arginine vasopressin and angiotensin II, and the chronotropic responses to exogenous isoprenaline, and by constructing chemoreflex and baroreflex function curves. Finally, to examine the possible role of changes in myocardial responsiveness to muscarinic cholinergic and β-adenergic stimulation in mediating alterations in the fetal heart rate response to acute hypoxaemia with glucocorticoid treatment or advancing gestational age, a novel Langendorff, biventricular, isolated, perfused fetal sheep heart preparation was developed.

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34

Leelayuwat, Naruemon. "Factors affecting metabolic responses to exercise after ingestion of a CHO meal". Thesis, University of Nottingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272836.

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35

Ells, Louisa J. "Post-prandial metabolic responses to ingestion of rapidly and slowly digested starches". Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399334.

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36

Adotey, Bless. "MATHEMATICAL MODELING OF CLOSTRIDIUM THERMOCELLUM’S METABOLIC RESPONSES TO ENVIRONMENTAL PERTURBATION". UKnowledge, 2011. http://uknowledge.uky.edu/bae_etds/1.

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Clostridium thermocellum is a thermophilic anaerobe that is capable of producing ethanol directly from lignocellulosic compounds, however this organism suffers from low ethanol tolerance and low ethanol yields. In vivo mathematical modeling studies based on steady state traditional metabolic flux analysis, metabolic control analysis, transient and steady states’ flux spectrum analysis (FSA) were conducted on C. thermocellum’s central metabolism. The models were developed in Matrix Laboratory software ( MATLAB® (The Language of Technical Computing), R2008b, Version 7.7.0.471)) based on known stoichiometry from C. thermocellum pathway and known physical constraints. Growth on cellobiose from Metabolic flux analysis (MFA) and Metabolic control analysis (MCA) of wild type (WT) and ethanol adapted (EA) cells showed that, at lower than optimum exogenous ethanol levels, ethanol to acetate (E/A) ratios increased by approximately 29% in WT cells and 7% in EA cells. Sensitivity analyses of the MFA and MCA models indicated that the effects of variability in experimental data on model predictions were minimal (within ±5% differences in predictions if the experimental data varied up to ±20%). Steady state FSA model predictions showed that, an optimum hydrogen flux of ~5mM/hr in the presence of pressure equal to or above 7MPa inhibits ferrodoxin hydrogenase which causes NAD re-oxidation in the system to increase ethanol yields to about 3.5 mol ethanol/mol cellobiose.

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37

Ghafouri, Khloud Jamil. "Effect of exercise, diet and ethnicity on metabolic responses in postprandial state". Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/8634/.

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Cardiovascular disease is a leading cause of mortality and morbidity worldwide. One of the key factors mediating cardiovascular disease risk, and the underlying atherogenic disease process, is disturbances to metabolism in the postprandial state, particularly with respect to lipoprotein metabolism. A number of studies have demonstrated that prior exercise can reduce postprandial triglyceride (TG) concentrations, with recent evidence indicating that increased clearance from the circulation of large very low density lipoproteins (VLDL1) plays an important role. However, it was unclear how exercise facilitated this potentially beneficial effect and this was the focus of the present work. The first experimental study in this thesis demonstrated, in 10 overweight/obese men, that 90 minutes of prior moderate exercise increased the affinity of VLDL1 for TG hydrolysis by lipoprotein lipase by 2.2-fold in the fasted state (p = 0.02) and 2.6-fold in the postprandial state (p = 0.001), but did not significantly alter the affinity of chylomicrons, a novel observation that adds to understanding of the mechanism by which exercise lowers TG concentrations. Postprandial responses to meal ingestion depend on the macronutrient composition of the food ingested. In the second experimental chapter, postprandial responses to ingestion of a test meal containing 75g glucose, or 75g fat, or a combination of 75g glucose and 75g fat were compared in 10 overweight/obese men. The main finding was that co-ingestion of fat with the glucose load reduced the postprandial glucose response, but not insulin response, compared with glucose ingestion alone. Co-ingestion of fat with the glucose load also substantially reduced the postprandial suppression of non-esterified fatty acids (NEFA) compared to glucose only ingestion. Postprandial TG responses were similar when only fat was consumed compared with co-ingestion of fat and glucose, but postprandial VLDL1 concentrations were lower in the latter condition. It is well established that ethnic differences exist in the prevalence of cardio-metabolic diseases. In particular, diabetes prevalence is high in Middle-Eastern populations. It is not known whether ethnic differences in postprandial metabolism contribute to these differences in risk. In the third experimental study, eight white European men and eight men of Middle-Eastern origin consumed a mixed-meal and postprandial responses were assessed. Postprandial insulin responses were higher in the Middle-Eastern men and postprandial TG concentrations were higher in the European men. This suggests that ethnic differences may exist in the inter-relationship between insulin resistance and lipoprotein metabolism. Thus, overall this thesis has provided insights into how postprandial metabolism is modulated by exercise, macronutrient intake and ethnicity.

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38

Vaughan, Jeremiah A. "Neuromuscular Function and Fatigue and Metabolic Responses while Cycling in the Heat". Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1542212848069694.

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39

Ibrahim, Mohammed. "Physiological and metabolic responses of two rose varieties to plant growth regulators". Thesis, Ibrahim, Mohammed (2018) Physiological and metabolic responses of two rose varieties to plant growth regulators. PhD thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/45991/.

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Rose (Rosa hybrida) is one of the most popular cut flowers with a worldwide production of more than 300 million stems per year. The perfume industry, which relies on a range of scented rose varieties, is also an important industrial application for roses. Among the numerous types of roses are some recent varieties including Hybrid Tea and Floribunda roses. The major problem in Australia is accelerated pre- and post-harvest flower drop and senescence, caused by deficiencies in endogenous plant growth regulators (PGRs). PGRs play important roles in the growth and development of flowers, especially in aromatic plants, stimulating the emission of volatile organic compounds (VOCs). The PGRs benzyladenine (BA) and naphthalene acetic acid (NAA) which belong to cytokinin and auxin group of PGRs respectively, are used by the floriculture industry as important growth regulators for promoting rose growth and development. However, it is still unknown that how these regulators and their application dosages influence rose plants. Therefore, this thesis aimed to evaluate and determine the efficacy of various concentrations of BA and NAA on arrange of morphological and physiological characteristics of roses to increase flowers longevity in two rose varieties (Floribunda and Hybrid Tea). In addition, this study was conducted to understand how different concentrations of BA and NAA effect the metabolic changes in different rose tissues together with a comparison of VOCs changes. This work in this thesis developed and optimized the headspace solid-phase microextraction (HS-SPME) with three-phase fibre 50/30μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) coupled with gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS) method for exploring and analysing VOCs emitted from the intact and excised flowers, leaves, and stems as well as from the rhizosphere and whole plants of the two rose varieties. This study has optimized different environmental factors involved in the performance of the two rose varieties was conducted, and three physiological characteristics photosynthesis rate, respiration rate, and chlorophyll content were assessed. Three different concentrations (0, 100 and 200 mg/L) of BA and NAA were applied to the two rose varieties, and different morphological and physiological characteristics were evaluated. For physiological effects (photosynthesis rate and chlorophyll index) studies, application of 200 mg/L of both BA and NAA were shown to increase plant height, numbers of branches and flowers, stem and flower diameters, length of flower stems and flower longevity, compared to the control. However, for the respiration rate, the control plants had significantly superior performance to the plants treated with 100 and 200 mg/L BA and NAA, for both rose varieties. The VOC profiles of the two rose varieties were characterized by the optimized HS-SPME-GC method. The effects of different concentrations (0, 100 and 200 mg/L) of BA and NAA on the VOCs emitted from different rose tissues for the two rose varieties were determined. The highest amounts extracted, and evaluated from the sum of peak areas were achieved after the application of 200 mg/L BA and NAA in both varieties. Of the emitted VOCs, 20 were significantly different in treated compare to non-treated Floribunda and Hybrid Tea roses from different rose tissues. Moreover, five compounds 4-heptyn-2-ol, cis-muurola-4(14)5-diene, γ -candinene, y-muurolene and prenyl acetate increased significantly after applications of 200 mg/L of BA and NAA. These five compounds have great potential to develop commercially important new rose growth regulators. The actual dosages of BA applied to the leaves was determined using filter paper as 11.16 mg/cm2 and 7.17 mg/cm2 for Hybrid Tea and Floribunda respectively. In conclusion, the application to rose plants of different concentrations of BA and NAA can promote a number of changes to both morphological and physiological parameters, and in turn have a significant effect on metabolite changes in different rose tissues. Application BA and NAA method could be applied to other floriculture plants to increase the flowers production in rose or other ornamental plants.

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40

Gordon, Kyle. "Metabolic and Thermal Responses to Short-Term, Intense Cold Water Acclimation Protocol". Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39532.

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Non-compensable cold exposure represents a potentially deadly threat to humans, as we lack highly specialized organs and mechanisms necessary to maintain our optimal core temperature of ~37°C. Repeated exposures to cold have been shown to induce protective physiological changes in cold responses through a process known as cold acclimatization (natural) or acclimation (in laboratory). The purpose of this thesis was to determine what physiological changes occur following an intense 7 day, 14°C cold water immersion acclimation protocol, during both non-compensable (Chapter 2) and compensable cold exposures (Chapter 3). This includes identifying changes in the contributions of the shivering (ST) and non-shivering (NST) thermogenic pathways to overall heat production. ST and NST changes were quantified via electromyography and indirect calorimetry, respectively. This 7 day cold water acclimation protocol resulted in a decrease in cooling rate, a significant increase in mean esophageal core temperature, a decrease in peak heart rate following immersion, and increased thermal comfort from day 1 to day 7 of the 1h 14°C cold water immersions. Further to these findings, changes in ST and NST were measured pre- and post-acclimation with a standardized compensable cold protocol using a liquid conditioned suit (LCS) which lowered Tskin to 26°C for 2.5h. The cold acclimation protocol resulted in a ~38% decrease in mean shivering over the 2.5h without any change in thermogenic rate from pre- to post-cold acclimation. In addition, no significant difference in fuel selection was observed. These results indicate that the short, intense cold acclimation protocol did result in a substantial change in the contribution of ST and NST to total heat production which could increase cold tolerance by reducing involuntary muscle contractions during ST.

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41

Shin, Damian. "Metabolic and physiological responses of cockroach, Periplaneta americana, nerve cord to osmotic stress". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ39882.pdf.

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42

Soita, Henry W. "The influence of forage particle size on rumen metabolic responses and nutrient utilization". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63924.pdf.

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43

Berg, Wiebke [Verfasser], i Kathrin [Akademischer Betreuer] Dausmann. "Metabolic responses to environmental variation in tropical reptiles / Wiebke Berg ; Betreuer: Kathrin Dausmann". Hamburg : Staats- und Universitätsbibliothek Hamburg, 2017. http://d-nb.info/1128820447/34.

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44

Ferreira, R. M. B. "The metabolic responses of plants to stress, with particular reference to protein turnover". Thesis, University of East Anglia, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376058.

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45

Wan, J. M.-F. "The effect of E. coli endotoxin on the metabolic responses of Wistar rats". Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376188.

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46

Berg, Wiebke Verfasser], i Kathrin H. [Akademischer Betreuer] [Dausmann. "Metabolic responses to environmental variation in tropical reptiles / Wiebke Berg ; Betreuer: Kathrin Dausmann". Hamburg : Staats- und Universitätsbibliothek Hamburg, 2017. http://nbn-resolving.de/urn:nbn:de:gbv:18-84374.

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47

Vazquez, Roman Karem Nathalie. "Metabolic Responses to Crude Oil during Very Early Development in Zebrafish (Danio rerio)". Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1707304/.

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The present study sought to determine some morphological and physiological critical windows during very early development in zebrafish exposed to crude oil. I hypothesized that exposed zebrafish would present a decrease in survival rate and body mass, and an increase in routine oxygen consumption (ṀO2), and critical oxygen tension (PCrit). To test these hypotheses, zebrafish were acutely exposed (24 h) during different days of development (1 to 6 days post-fertilization, dpf) to different concentrations of high-energy water-accommodated fractions (HEWAFs). The endpoints of survival, body mass, routine oxygen consumption, and critical oxygen partial pressure were measured at 7 dpf. Survival rate decreased based on the exposure concentration but not as a function of the day of crude oil exposure. No significant effects were found in PCrit. Body mass was reduced by the different concentrations of HEWAF, with the size of the effect varying with exposure day, with the effect strongest on when exposure occurred at 2 and 3 dpf. Oxygen consumption (ṀO2) differed significantly depending upon the day of exposure in fish exposed to crude oil. Specifically, HEWAF exposure significantly increased ṀO2 in larvae exposed at 3 dpf (9.081 µmol O2/g/h, ±0.559) versus 2 dpf (6.068 µmol O2/g/h, ±0.652) and 6 dpf (6.485 µmol O2/g/h, ±0.609). Overall, the main effects on body mass and ṀO2 occurred at crude oil exposures during 3 dpf. The presence of a critical window in fish is proposed at this developmental time, which coincides with the hatching period.

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48

Cheng, Jun. "MONITORING METABOLIC RESPONSES IN SACCHAROMYCES CEREVISIAE USING FLUORESCENCE-BASED DETECTION OF NADH CONFORMATION". Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1313788354.

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49

Li, Shengchun. "Antioxidant systems and protein phosphatases in metabolic and signaling responses to oxidative stress". Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112086.

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Le stress oxydant est un acteur clé dans les réponses des plantes à des conditions contraignantes. En raison de la complexité de la régulation de l’état redox cellulaire, il reste beaucoup à élucider concernant les interactions entre différentes composantes dans ces conditions. Grâce à une approche de génétique inverse basée sur un mutant d’Arabidopsis déficient en catalase (cat2) qui présente des modifications d’état redox prévisibles et bien définies, cette étude a exploré les interactions entre le stress oxydant et (1) un gène spécifique impliqué dans la déphosphorylation des protéines, (2) des enzymes spécifiques impliquées dans les systèmes antioxydants réducteurs. Les résultats obtenus révèlent que la sous-unité B'γ de la protéine phosphatase de type 2A (PP2A-B'γ) est importante dans la détermination des phénotypes et des réponses de défense photopériode-dépendantes chez cat2. En conditions de jours courts (SD), un double cat2 pp2a-b'γ mutant montrait une gamme de réponses qui n’étaient pas observées chez cat2. Ces effets comprenaient l’apparition de lésions ainsi que l’accumulation de l’acide salicylique et d’autres composés de défense. Des analyses métabolomiques et protéomiques ont permis de démontrer que ces effets étaient accompagnés de modifications de l’abondance de métabolites et protéines spécifiques, ainsi que des changements dans le statut de phosphorylation de certains polypeptides. Dans un deuxième volet du travail, l’importance d’une enzyme productrice du NADPH a été évaluée en produisant des doubles cat2 nadp-me2 mutants chez lesquels l’isoforme majeure de l’enzyme malique cytosolique n’est plus exprimée. Malgré une induction de cette enzyme par le stress oxydant aux niveaux de transcrits et d’activité, et une diminution importante de l’activité foliaire associée aux mutations nadp-me2, peu de différence a été observée entre les lignées cat2 et cat2 nadp-me2. De même, la mutation nadp-me2 n’a pas affecté la réponse phénotypique de plantes exposées à l’ozone. Dans la troisième partie du travail, le couplage entre les pools ascorbate et glutathion lors du stress oxydant a été exploré par l’introduction de mutations pour la déshydroascorbate réductase (DHAR) dans le fond génétique cat2. L’activité extractible de cette enzyme a été diminuée à des niveaux très faibles chez des lignées portant à la fois les mutations dhar1 et dhar3. Cependant, peu de différence a été observée dans les phénotypes et les statuts d’ascorbate et de glutathion chez un triple mutant cat2 dhar1 dhar3 par rapport à cat2. Des analyses préliminaires d’un quadruple cat2 dhar1 dhar2 dhar3 mutant semblent pourtant indiquer que les trois DHARs jouent des rôles fonctionnellement redondants dans le stress oxydant. Dans son ensemble, ces travaux apportent des données nouvelles sur les enzymes qui régulent les réponses aux stress oxydants et ont généré des outils intéressants pour des études ultérieures
Oxidative stress is a key player in plant responses to challenging environmental conditions. The intricate nature of the regulation of cellular redox state means that much remains to be elucidated on interactions between different components in these conditions. By using a genetic approach based on a catalase-deficient Arabidopsis mutant (cat2) that presents well-defined, predictable changes in redox state, this study explored interactions between oxidative stress and (1) a specific gene involved in protein dephosphorylation, and (2) specific enzymes involved in the antioxidative/reducing system. The results showed that protein phosphatase 2 subunit B'γ (PP2A-B'γ) is involved in determining day length-dependent phenotypes and related defense responses in cat2. A cat2 pp2A-B'γ double mutant showed a range of responses that were not observed in cat2 grown in short days, including lesion formation and accumulation of salicylic acid (SA) and related metabolites. Metabolomics and proteomics analyses showed that these effects were associated with altered abundance of specific metabolites and proteins, as well as changes in protein phosphorylation status. A second part of the study investigated the importance of NADP-generating enzymes in oxidative stress by production of cat2 nadp-me2 double mutants, in which the cytosolic isoform of NADP-malic enzyme is knocked out. Although NADP-ME2 was shown to be induced by oxidative stress, and mutants for this gene had much decreased leaf NADP-malic enzyme activity, no effects on cat2 phenotypes or redox profiles were apparent. Similarly, phenotypic responses to ozone were not affected in an nadp-me2 single mutant. In the third part, coupling between ascorbate and glutathione pools during oxidative stress was investigated by introduction of loss of function mutations for dehydroascorbate reductase (DHAR) into the cat2 background. In lines carrying a combination of dhar1 and dhar3 mutations, extractable leaf activity was decreased to very low levels. Despite this, cat2 dhar1 dhar3 and cat2 phenotypes and ascorbate and glutathione pools were similar. However, preliminary functional analysis of a cat2 dhar1 dhar2 dhar3 quadruple mutant suggested that the three DHARs play functionally redundant roles in oxidative stress. Overall, the work provides new data on enzymes that regulate responses to oxidative stress and has produced interesting genetic tools for further study

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Batista, Aline Duarte. "Metabolic responses of Chlamydomonas reinhardtii CC125 under different proportions of urea and ammonium". Universidade Federal de Viçosa, 2017. http://www.locus.ufv.br/handle/123456789/21093.

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Chlamydomonas reinhardtii (filo Chlorophyta) é um organismo modelo amplamente utilizado para estudos de carência de nitrogênio (N), no intuito de avaliar a acumulação de lipídeos, alterações na bioenergética e a regulação da fotossíntese. As clorófitas podem incorporar N inorgânico e orgânico, e a fonte de N utilizada influencia no padrão de acúmulo de lipídeos. As fontes inorgânicas mais frequentemente disponíveis são amônio (NH 4+ ), nitrato (NO 3- ) e nitrito (NO 2- ); enquanto as fontes orgânicas mais comuns são purinas, ureia e aminoácidos. O uso de ureia por outras clorófitas usualmente promove melhoras no crescimento, na produção de lipídeos e biomassa quando comparado ao NH 4+ . Contudo, para C. reinhardtii faltam informações mais específicas de como o seu metabolismo responde à assimilação de ureia. Assim, neste trabalho estudou-se o metabolismo e o crescimento de C. reinhardtii CC125 em ureia como única fonte nitrogenada, bem como diferentes proporções de ureia combinada com NH 4+ . Alíquotas de C. reinhardtii CC125 foram mantidas em crescimento mixotrófico em meio TAP (Tris- Acetato-Fosfato), sob temperatura de 24±2 ° C, fotoperíodo de 16:8 h (luz: escuro), 90 μmol fótons m -2 s -1 e constante agitação a 110 rpm. Cinco tratamentos foram testados: (i) 100% NH 4+ (0,4 g L -1 NH 4 Cl); (ii) 25% ureia (0,3 g L -1 NH 4 Cl e 0,11 g L -1 ureia); (iii) 50% ureia (0,2 g L -1 NH 4 Cl e 0,21 g L -1 ureia); (iv) 75% ureia (0,1 g L -1 NH 4 Cl e 0,32 g L -1 ureia); e (v) 100% ureia (0,42 g L -1 ureia). Os tratamentos foram avaliados na fase logarítmica (LOG) após 50 h de cultivo e na fase estacionária (STA), após 240 h de crescimento. O número de células, área celular, biomassa livre de cinzas, os conteúdos de clorofila a e b, aminoácidos, amido, proteínas, carboidratos e lipídeos foram determinados nas fases LOG e STA. O perfil metabólico e de ácidos graxos foram determinados na fase STA. O crescimento observado nos meios com ureia foi similar ao 100% NH 4+ , quando comparadas as curvas e os parâmetros de crescimento. O número de células foi superior nos tratamentos com menos ureia, tanto na fase LOG quanto STA. Na fase LOG não houve diferença nos totais de clorofila a e b, aminoácidos e proteínas. Na fase STA os níveis de clorofila total bem como clorofila a foram maiores nos tratamentos 75% e 100% ureia. Os totais de clorofila b e proteínas solúveis totais aumentaram com o aumento de ureia. Os níveis de carboidratos, na fase LOG, foram maiores no tratamento 100% ureia. Na fase STA, os maiores valores obtidos foram dos tratamentos 100% ureia e 100% NH 4+ . O tratamento 100% ureia produziu maior quantidade de lipídeos nas duas fases de crescimento analisadas. A quantificação de açúcares indicou que alguns dissacarídeos aumentaram nos tratamentos com mais de 75% de ureia. Dos 14 ácidos orgânicos quantificados, 11 diminuíram no tratamento com 25% de ureia, assim como muitos aminoácidos. Quatro intermediários do ciclo TCA (citrato, isocitrato, succinato e malato) aumentaram no tratamento 100% ureia. O perfil de ácidos graxos foi modificado pelas concentrações de NH 4+ e ureia em C. reinhardtii: O total de ácidos graxos saturados (ΣSFA) aumentou com o aumento de ureia, porém o total de ácidos graxos monoinsaturados diminuiu com o aumento de ureia. O ácido graxo mais abundante foi o ácido palmítico (C16:0) e apresentou uma tendência ao aumento com o aumento de ureia no meio. A porcentagem de ácido oleico (C18:1 w8) decresceu com o amento de ureia, enquanto as porcentagens do ácido linoleico (C18:2 w6) dobrou nos tratamentos que continha ureia. Logo, nossos dados indicam que quanto maior a disponibilidade de ureia, maiores são as mudanças no metabolismo de Carbono (C) e N, sem, contudo, promover drásticas mudanças no crescimento. Além disso, nossos resultados sugerem que a ureia pode fornecer C adicional para a biossíntese, alterando a razão C:N no meio e promovendo mudanças no total de lipídeos e no perfil de ácidos graxos produzidos.
Chlamydomonas reinhardtii (phylum Chlorophyta) as a model organism for nitrogen (N) starvation studies in order to evaluate lipid accumulation, changes in bioenergetics and the regulation of photosynthesis. Chlorophytes can incorporate N in inorganic or organic form and the source of N influences the accumulation of lipids. The most frequently available inorganic sources are Ammonium (NH 4+ ), Nitrate (NO 3- ) and Nitrite (NO 2- ) and the most common organic sources are purines, urea and amino acids. Use of urea in others chlorophytes usually promotes enhancement in both growth, lipid production and biomass when compared to NH 4+ . However, for C. reinhardtii there is a lack of more specific information on how their metabolism responds to the assimilation of N organic sources. Thus, in this work we studied the metabolism and growth of C. reinhardtii CC125 in urea as the only N source as well as combined with NH 4+ . Aliquots of C. reinhardtii CC125 were maintained in mixotrophic growth in TAP (Tris-Acetate-Phosphate) medium under temperature between 24±2 ° C, photoperiod of 16:8 h (light: dark), 90 μmol photons m -2 s -1 and constant shaking of 110 rpm. Five treatments were carried out: (i) 100% NH 4+ (0,4 g L -1 NH 4 Cl); (ii) 25% urea (0,3 g L -1 NH 4 Cl and 0,11 g L -1 urea); (iii) 50% urea (0,2 g L -1 NH 4 Cl and 0,21 g L -1 urea); (iv) 75% urea (0,1 g L -1 NH 4 Cl and 0,32 g L -1 urea); and (v) 100% urea (0,42 g L -1 urea). The treatments were evaluated in the logarithmic phase (LOG), after 50 hours of growth and in the stationary phase (STA), after 240 hours of growth. The number of cells, cell area, ash-free dry weight, chlorophyll a and b contents, amino acids, starch, proteins, total carbohydrates and lipids were determined at LOG and STA phases. The metabolic profile and fatty acids profile was determined at STA phase. The growth observed in medium with urea was similar to 100% NH 4+ by comparing growth curves and kinetic growth. The number of cells after in LOG and STA phase was higher in treatments with lower percentage of urea. Determination of total chlorophyll a and b, free amino acids and proteins showed no differences between treatments in the LOG phase. At STA phase level of total chlorophyll as well as chlorophyll a were higher in 75 and 100% urea. The levels of chlorophyll b and total soluble proteins increased with increasing urea. The levels of carbohydrates, in the LOG phase, were higher in 100% urea treatment. In the STA phase, the highest values were observed for 100% urea and 100% NH 4+ treatments. 100% urea treatment produced more lipids than other treatments in the two growth phases. Quantification of sugars indicated that disaccharides increased in treatments with more than 75% urea. Out of 14 quantified organic acids, 11 decreased in the treatment with 25% of urea as well many amino acids. Four intermediates of TCA cycle (citrate, isocitrate, succinate and malate) increased in the treatment with 100% urea. The FAMEs profile of C. reinhardtii was altered by concentration of NH 4+ and urea: Total saturated fatty acids (ΣSFA) increase with amount of urea; however, total monounsaturated fatty acids (ΣMUFA) decrease with amount of urea. The most abundant fatty acid observed was palmitic acid (C16:0) which there is a tendency to increased with the amount of urea in the medium. The percentage of oleic acid (C18:1 w8) decreased with amount of urea, while percentages of linoleic acid (C18:2 w6) doubled in treatments containing urea. Thus, our data indicate that higher the availability of urea, higher are the Carbon (C) and N metabolism changes, without, however, promoting drastic changes in growth. In addition, our results suggest that urea might also provide additional C, altering C:N ratio in medium and lead changes in lipids and total fatty acid production and profile.

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