Academic literature on the topic 'Rats – Reproduction – Endocrine aspects'

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Journal articles on the topic "Rats – Reproduction – Endocrine aspects"

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Badger, Thomas M., Martin J. J. Ronis, and Reza Hakkak. "Developmental Effects and Health Aspects of Soy Protein Isolate, Casein, and Whey in Male and Female Rats." International Journal of Toxicology 20, no. 3 (May 2001): 165–74. http://dx.doi.org/10.1080/109158101317097755.

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Dietary factors other than the traditional nutrients are found in the so-called functional foods. They are becoming increasingly recognized as potentially important for maintaining good health. Soybeans are rich in such factors thought to help prevent certain chronic diseases. Soy protein isolate (SPI) is one of the three major proteins used in infant formulas sold in the United States, with casein (CAS) and whey (WPH) proteins being the others. We have been studying the health effects of these proteins. Safety concerns have developed over the consumption of soy-based infant formula, partly because of the high circulating levels of the total isoflavones (phytoestrogens) during “critical periods of infant development.” There is a paucity of data on developmental, physiological, neurophysiological, behavioral, metabolic, or molecular effects of soy phytochemicals in humans, especially during pregnancy and infancy. We have studied the effects of CAS, SPI, and WPH in short-term, long-term, and multigenerational studies in rats. Aside from minor differences in body weight gain profiles, CAS-, SPI-or WPH-fed rats did not differ in development, organ weights, in vitro hepatic metabolism of testosterone (T), or reproductive performance. However, some endocrine-related functions differed between rats fed these proteins. We found that SPI accelerated puberty in female rats ( p <.05) and WPH delayed puberty in males and females, as compared with CAS ( p <.05). Gender differences were also found in gonadectomy-induced steroid responses. Male rats had normal serum T levels, but female rats fed SPI had reduced serum 17β-estradiol concentrations and a blunted 17β-estradiol response to ovariectomy, as compared to rats fed CAS or WHP ( p <.05). Female rats fed SPI or WHP or treated with genistein had reduced incidence of chemically induced mammary cancers ( p <.05) compared to CAS controls, with WHP reducing tumor incidence by as much as 50%, findings that replicate previous results from our laboratory. Together, these results suggest gender-specific differences in development and certain endocrine responses among rats fed diets composed of a single protein source such as those used in infant formulas. Whether similar developmental effects occur in human infants is unknown, but unlikely because (1) most infants do not consume such diets throughout life as these rats did, and (2) no such effects have been reported in millions of American infants fed infant formula containing these proteins. The long-term health consequence implications of early diet exposure to SPI and WPH, such as reduced breast cancer incidence, are likely to be very positive.
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Gerardin, Daniela C. C., Renata C. Piffer, Patrícia C. Garcia, Estefânia G. Moreira, and Oduvaldo C. M. Pereira. "Effects of maternal exposure to an aromatase inhibitor on sexual behaviour and neurochemical and endocrine aspects of adult male rat." Reproduction, Fertility and Development 20, no. 5 (2008): 557. http://dx.doi.org/10.1071/rd07213.

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The present study examined the effects of letrozole exposure during brain sexual differentiation on endocrine, behavioural and neurochemical parameters in male rat descendants. Pregnant female rats received 1 mg kg–1 day–1 letrozole or vehicle by oral gavage on gestational Days 21 and 22. Exposure to letrozole reduced anogenital distance in males on postnatal Day (PND) 22. At adulthood (PND 75), plasma testosterone levels and hypothalamic dopaminergic activity were increased, but sexual competence was impaired, because fewer successful sexual behaviours (mount, intromission and principally ejaculation) were observed. The impairment of reproductive function by prenatal exposure to an aromatase inhibitor reinforces the importance of adequate oestrogenic activity during perinatal sexual differentiation for complete masculinisation of the hypothalamus.
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Valentim, Jean Kaique, Janaína Palermo Mendes, Bruna Barreto Przybulinski, Felipe Cardoso Serpa, Deivid Kelly Barbosa, Vivian Aparecida Rios Castilho, and Rita Therezinha Rolim Pietramale. "Fatores Nutricionais Aplicados à Reprodução de Ruminantes." UNICIÊNCIAS 23, no. 2 (December 4, 2019): 77. http://dx.doi.org/10.17921/1415-5141.2019v23n2p77-82.

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Os animais de produção estão sendo modificados através de um intenso melhoramento genético, buscando intensificar seu desempenho para atender a demanda mundial em quesitos de alimentação. Essa maximização de desempenho demanda um acréscimo nutricional, e este por sua vez pode afetar as funções reprodutivas. Vários estudos mostram que a reprodução pode ser comprometida se as necessidades nutricionais dos animais não forem atendidas. Esta demanda nutricional afeta diretamente a função dos órgãos reprodutivos e o funcionamento do sistema endócrino, podendo interferir na taxa de fertilidade destes animais. A nutrição tem influência na fertilidade, diretamente por meio do fornecimento de nutrientes específicos, que são necessários para os processos de desenvolvimento do folículo, de ovulação, de maturação oocitária, de fertilização, de sobrevivência embrionária e o estabelecimento da gestação e, indiretamente, atuando sobre as concentrações circulantes dos hormônios e outros metabólitos sensíveis aos nutrientes que são requeridos para o sucesso destes processos. O objetivo do presente trabalho é obter uma revisão de literatura atualizada sobre o contexto recente da influência de fatores nutricionais sobre os aspectos reprodutivos de animais ruminantes. Palavras-chave: Nutrição. Metabolismo. Fertilidade. Ruminantes. AbstractThe farm animals are being modified through an intensive genetic improvement seeking to increase their performance to meet the global demand on power issues. This performance maximization demands an extra nutritional and this in turn can affect the reproductive functions. Several studies show that the reproduction can be compromised if the animal’s nutritional needs are met. This nutritional demand directly affects the function of the reproductive organs and the functioning of the endocrine system and may interfere with fertility rate of these animals. Nutrition affects fertility, directly through the provision of specific nutrients that are required for the processes of development of follicle maturation, ovulation, oocyte , fertilization, embryo survival and the establishment of pregnancy; and, indirectly, acting on circulating concentrations of hormones and other metabolites sensitive to nutrients that are required for the success of these processes. The goal of this work was to obtain an updated literature review with recent studies related to nutritional aspects involved in the ruminant animals reproduction. Keywords: Nutrition. Metabolism. Fertility. Ruminants.
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Nurdiana, Nurdiana, Pradnyawati Chania, Rifzi Nurvitasari, Azmiatun Nisa, Styan Wahyu Diana, Evalina Izzatur Rochmah, Elly Mayangsari, et al. "The Effect of Soy Milk on Mounting Latency, Mounting Frequency, and Reproductive Development in Male Wistar Rats (Rattus Norvegicus)." Open Access Macedonian Journal of Medical Sciences 9, B (August 17, 2021): 670–78. http://dx.doi.org/10.3889/oamjms.2021.6416.

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AIM: This research aims to examine the effects of soy milk on mounting latency (ML), mounting frequency (MF), estrogen levels, androgen-binding protein (ABP) expression, and spermatogenesis in male rats (Rattus norvegicus). METHODS: Twenty-four male wistar rats (Rattus norvegicus) aged 4 weeks were divided into four groups. Control group (given a normal diet), P1; P2; P3 (given the normal diet and soy milk powder at doses of 7.1; 14.2; 21.3 g/KgBW/day, respectively) for 6 weeks. Observation of ML and MF were performed at 9 weeks 5 days of age, and rat surgery was performed at 10 weeks of age. Analysis of estrogen hormone levels was conducted by enzyme-linked immunosorbent assay (ELISA), ABP staining was using immunohistochemistry method, testicular spermatogenesis was observed using histopathological methods, and observation of spermatozoa was performed under the microscope. RESULTS: The results showed no significant reduction of ML and MF, estrogen levels, and ABP expression (p ≤ 0.256; 0.865; 0.959, respectively) in male rat, but there was a significant decrease in the number, morphology, motility of spermatozoa, and testicular histophatology, (p ≤ 0.000, 0.003, 0.008, 0.000, respectively). CONCLUSION: The administrassion of soy milk in various doses (7.1;14.2;21.3 g/KgBW/day) in male Wistar rats (Rattus norvegicus) had showed significantly difference on histopathological evaluation using Johnson’s scoring system, sperm quantity and quality, while on mounting latency and frequency, estrogen levels, and ABP expressions did not show significantly difference between groups. That describe of isoflavone in soy milk can affect several aspects related to male endocrine and reproductive development.
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Klowden, Marc J. "Endocrine aspects of mosquito reproduction." Archives of Insect Biochemistry and Physiology 35, no. 4 (1997): 491–512. http://dx.doi.org/10.1002/(sici)1520-6327(1997)35:4<491::aid-arch10>3.0.co;2-5.

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Seliukova, N. Yu, K. V. Misyura, and G. V. Storozhenko. "EXPERIMENTAL MODELS OF FETOPLACEENTAL INSUFFICIENCY IN ANIMALS (LITERATURE REVIEW AND OWN OBSERVATIONS)." Актуальні проблеми сучасної медицини: Вісник Української медичної стоматологічної академії 20, no. 4 (December 30, 2020): 225–31. http://dx.doi.org/10.31718/2077-1096.20.4.225.

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This literature review is devoted to experimental models of placental disorders in animals. Today, our knowledge of the structure and function of the placenta during pregnancy is remaining limited. The use of new technologies and imaging methods in animals that can provide safe monitoring of the growth and function of the placenta in vivo requires preclinical studies and trials in appropriately developed animal models that can be easily translated into a clinical setting. All this, of course, requires the use of test animals for modelling placental pathologies. The review considers the positive and negative aspects of various animals and methods of modelling the pathological conditions during pregnancy. In the experiment, models of fetoplacental insufficiency are very often used, arising from oxidative stress and activation of free radical oxidation. To simulate the experimental fetoplacental insufficiency caused by histotoxic hypoxia, the xenobiotic tetrachloromethane is used. Women of very young and mature reproductive age have a high risk of fetoplacental insufficiency. It is not known exactly how placental insufficiency in mothers will affect the sexual development of pubertal offspring. That is why we conducted a comprehensive experimental study on this issue at the base of V. Danilevsky Institute of Endocrine Pathology Problems, NAMS of Ukraine. To solve this problem, our institute has developed and proposed a new pharmaceutical composition that should not only contribute to the correction of placental insufficiency, but also has a certain prophylactic value for maintaining reproductive potential in adulthood. The study was carried out on Wistar rats of two age groups. We modelled experimental fetoplacental insufficiency and then corrected it with this pharmaceutical composition. Our study made it possible to establish that fetoplacental insufficiency has a different effect on the formation of the reproductive system in male and female rats in puberty. Prophylactic adding of the composition to the food for pregnant female rats with modelled placental insufficiency leads to the decrease in reproductive diseases of their offspring in puberty. Research on animal models provides important insight into the molecular and functional mechanisms underlying fetoplacental insufficiency and intrauterine growth retardation, as it enables to carry out studies, which are not possible in pregnant women.
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Tomatis, Veronica, Christian Battipaglia, and Alessandro D. Genazzani. "Thyroid, Adrenal, PRL Impairments and Ovarian Function." Endocrines 2, no. 3 (July 27, 2021): 212–25. http://dx.doi.org/10.3390/endocrines2030021.

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Endocrine axes (prolactin, thyroid and adrenal axes) directly and indirectly modulate and drive human female central functions, mainly behavior and reproduction. Though having distinct abilities, they greatly act both at peripheral as well as at neuroendocrine levels, so as to participate in the control of reproduction. Any event that changes these balanced activities produces specific peripheral signals that induce abnormal functions centrally, thus triggering menstrual disorders such as oligomenorrhea or amenorrhea. It is clear that the knowledge of the relationships that exist between the different endocrine axes becomes essential for the choice of therapeutical approach. This review aims to focus on the main aspects of the physiopathology of the endocrine diseases that might be at the basis of that interference with female reproductive capacity.
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Chen, Hao, Zhaoping Liu, Xiaopeng Zhang, Xudong Jia, Qian Li, Qing Su, and Wei Wang. "Assessment of synergistic thyroid disrupting effects of a mixture of EDCs in ovariectomized rats using factorial analysis and dose addition." Toxicology Research 5, no. 6 (2016): 1585–93. http://dx.doi.org/10.1039/c6tx00193a.

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Phillips-Farfán, Bryan V., and Alonso Fernández-Guasti. "Endocrine, neural and pharmacological aspects of sexual satiety in male rats." Neuroscience & Biobehavioral Reviews 33, no. 3 (March 2009): 442–55. http://dx.doi.org/10.1016/j.neubiorev.2008.11.003.

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van der Ven, Leo T. M., Ton van de Kuil, Pim E. G. Leonards, Wout Slob, Hellmuth Lilienthal, Sabina Litens, Maria Herlin, et al. "Endocrine effects of hexabromocyclododecane (HBCD) in a one-generation reproduction study in Wistar rats." Toxicology Letters 185, no. 1 (February 2009): 51–62. http://dx.doi.org/10.1016/j.toxlet.2008.12.003.

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Dissertations / Theses on the topic "Rats – Reproduction – Endocrine aspects"

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Zhang, Song. "Peripheral and central pathways linking metabolic status and reproduction in male sheep." University of Western Australia. School of Animal Biology, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0037.

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[Truncated abstract] Reproductive activity is affected by external factors such as photoperiod, social cues, stress and nutrition, all of which can alter the pulsatile activity of the GnRH neurons, which is the major neuroendocrine system used by the brain to control gonadal function. In the male Merino sheep, nutrition is one of the most powerful factors that affect pulsatile LH secretion, used commonly to bioassay GnRH neuronal activity. More accurately, the reproductive system responds to “metabolic status”, rather than “nutrition”, and the three factors that contribute to metabolic status are food intake, the amount of body reserves and the rate of energy expenditure ... In this thesis, I tested the general hypothesis that the metabolic hormones and hypothalamic neuropeptides that are known to control food intake also mediate the effect of metabolic status on the activity of the GnRH neurons ... In conclusion, the results from my experiments provide some insight into the mechanisms by which metabolic status affects reproductive activity in male sheep. Plasma insulin, which changes with alterations in metabolic status, appears to play a critical role in the regulation of GnRH neuronal activity. The level of leptin seems to have a permissive role only in lean animals. Orexins acting via OX2 receptors could be involved in the activation of reproductive function following an acute increase in nutrition. However, the neuropeptidergic systems can not be ruled out because they might be involved in very early steps of responses to nutrition.
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Abdo, Michael A. "Tumour necrosis factor : alpha signal transduction in rat corpus luteum apoptosis." University of Western Australia. School of Anatomy and Human Biology, 2002. http://theses.library.uwa.edu.au/adt-WU2003.0024.

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[Formulae and special characters can only be approximated here. Please see the pdf version of the abstract for an accurate reproduction.] Apoptosis is a morphologically distinct form of cell death that is involved in the regulation of normal and aberrant cell systems. The complexities of the apoptotic cell death pathway arise from variation in both the cellular specialisation and initial stimulus. The corpus luteum (CL) is an endocrine gland that whilst critical to the maintenance of pregnancy in the rat, regresses at the completion of each oestrous cycle and pregnancy. This regression is facilitated through apoptosis; though, the stimulus and factors involved in the apoptotic pathway are poorly understood. Previous studies suggest that CL regression is not initiated through failure of luteotrophic support, but rather the active production of a luteolytic factor, of which tumour necrosis factor -alpha (TNFα) is one possible candidate. Several publications have reported the participation of the immune system in ovarian events. There is evidence that TNFα expression within the ovary is coordinated between cells of the immune system and the hormonal regulation of the CL. This study has focussed on the role of TNFα in CL apoptosis and the factors involved in this apoptotic pathway. TNFα-induced cell death is governed by the presence of the two TNFα receptors (TNFR) and several second messenger systems that include; the sphingolipids, mitogen-activated protein (MAP) kinases, nitric oxide (NO), nuclear factor-kappaB (NF-κB) and the caspases. These factors and their interactions were assessed in the rat CL during pregnancy and post-partum, and in vitro. Apoptosis was measured through the analysis of DNA fragmentation using DNA 3’ end labelling and single cell electrophoresis (COMET assay). Assessment of mRNA and protein expression was through Real-time RT-PCR and Western blot analysis; proteins were localised within the CL by immunocytochemistry. In addition, specific measurement of sphingolipid expression and nitric oxide (NO) production was by high performance liquid chromatography (HPLC) and NO assay respectively. Following parturition, TNFα mRNA and protein expression increased corresponding to the onset of CL apoptosis and increased expression of the chemotactic factor monocyte chemoattractant protein -1 (MCP-1). Furthermore, CL apoptosis was induced by treatment with recombinant TNFα in a time- and dose-dependent manner. A similar effect was observed in isolated luteal cells. Simultaneously, the functional regression of the CL was assessed by measurement of both progesterone synthesis and steroidogenic acute regulatory (StAR) protein expression. StAR mRNA and protein expression declined toward parturition in vivo. Immunocytochemical studies revealed the presence of TNFα receptors 1 (TNFR1) and 2 (TNFR2) in luteal cells. Furthermore, TNFR mRNA was isolated from CL throughout pregnancy and post-partum. Subsequently, the role of the sphingolipids ceramide and sphingosine was examined during CL apoptosis in vitro. Ceramide and sphingosine were found to be potent apoptotic agents when administered in vitro (50µM). The downstream signal transduction of TNFα and ceramide was assessed through MAP kinase expression. Both TNFα and ceramide increased expression of the pro-apoptotic p38 MAP kinase with no change to the non-apoptotic extracellular signal-related kinase (ERK1&2). Despite previous reports of c-Jun NH2 terminal kinase (JNK) involvement in the cell death pathway, JNK expression was not evident in the rat CL. The caspases are a family of cysteine proteases central to the regulation and execution of apoptosis. General inhibition of the caspase cascade in vitro was effective in preventing apoptosis regardless of the apoptotic stimulus (TNFα, ceramide and sphingosine), suggesting that this pathway is central to CL apoptosis. Specific inhibition of several caspases produced a varying effect; inhibition of caspases 3, 6 and 8 significantly reduced the level of TNFα-induced apoptosis, thus supporting their classification as either regulatory or effector caspases. NO is endowed with the unique ability to initiate and to block apoptosis and this dichotomy extends to the cytotoxic actions of TNFα. Inhibition of NO production by treating CL with L-NAME prevented the onset of apoptosis, whilst NO production increased in response to increasing levels of apoptosis following trophic withdrawal. However, this effect was not seen during TNFα-induced apoptosis, suggesting that the actions of NO are independent of TNFα. The data presented within this study examine multiple elements of the TNFα cell death pathway in a single system. The results suggest that these elements are involved in TNFα signal transduction and furthermore, in rat CL apoptosis. It can be said that TNFα plays an active role in CL regression through the activation of the caspases, the sphingolipids and the MAP kinases.
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Pryor, Andrew William. "Reproduction and Endocrine Aspects of Early and Mid Lactation Holstein Cows." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/32486.

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This study was designed to determine the effects of stage of lactation and subsequent energy status on metabolic and endocrine measures, follicular development, and the quality of oocytes obtained from Holstein cows. Holstein cows were selected prior to calving and assigned to the early lactation (EL) group (n=8) while, cows at d 90 postpartum were selected for the mid-lactation (ML) group (n=7). Blood samples were taken twice weekly from 4 wk prior to the start of follicular aspirations and then on through the aspiration periods for metabolite and hormone determination. Ultrasound-guided transvaginal follicular aspiration (TVFA) was conducted twice weekly for a 10-wk period on all cows. Follicular fluid samples were obtained from the largest follicle, > 10 mm in diameter, for hormone determination. All data were analyzed by ANOVA, using the general linear model procedures. Mean energy balance was positive for (2.43 ± 0.32 Mcal/kg) for ML cows and negative (-1.55 ± 0.33 Mcal/kg) for EL cows. In ML cows serum progesterone (P4) decreased rapidly from 2.7 ± 0.1 ng/ml at the first aspiration session to a nadir of 0.33 ± 0.1 ng/ml at wk 8, while follicular fluid P4 increased from 0.9 ± 0.5 to 5.6 ± 0.5 ng/ml. In the EL cows serum and follicular fluid P4 remained relatively constant over the course of aspirations. There was a linear increase in follicular fluid insulin-like growth factor I (IGF-I) for EL and ML cows, however the increase was more rapid for ML cows (159 ± 36 to 200 ± 36 ng/ml) than for EL cows (145 ± 36 to 164 ± 36 ng/ml). Over the aspiration period nonesterified fatty acids (NEFA) declined rapidly for the EL cows (0.32 ± 0.2 to 0.22 ± 0.2 mEq/L), while serum NEFA for the ML cows were relatively stable (0.19 ± 0.2 to 0.22 ± 0.2 mEq/L). The number of follicles observed during the aspiration sessions increased linearly for both EL and ML cows (P < 0.05) over the 10-wk period. However, the increase was larger for the ML cows than for the EL cows, going from 14.2 ± 0.5 to 18.1 ± 0.5 and 14.9 ± 0.3 to 15.7 ± 0.5, respectively. These results show that cows in early lactation are physiologically under more production stress than cows in mid lactation. Furthermore, increasing levels of serum and follicular fluid IGF-I in mid lactation may reflect differences in follicle and oocyte measures.
Master of Science
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Melnyk, Peter M. (Peter Michael). "Estrogen regulation of testicular function in the adult ram." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59414.

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During the nonbreeding season (July), three groups of five Dorset x Leicester x Suffolk rams were assessed over a period of 5 days. One group of rams (control) was implanted (sc) with five 5cm empty Silastic capsules (i.d. 3.4mm, o.d. 4.6mm); two other groups, designated as Low-E$ sb2$ and High-E$ sb2$, received five estradiol filled capsules of either 5cm or 10cm, respectively for 4 days. Estradiol treatment elevated serum estradiol concentration about 150% in the Low-E$ sb2$ groups (15.7 $ pm$ 1.3 pg/ml) and 300% in the High-E$ sb2$ groups (26.6 $ pm$ 2.4 pg/ml) compared with controls (6.3 $ pm$ 0.8 pg/ml). In the absence of LH pulsing, mean LH, FSH and testosterone concentrations were all decreased significantly (P $<$.05) with increasing estradiol concentration, while PRL concentration was increased (P $<$.05) by as much as 105%. In the LH-pulsed groups, LH-peak height on day 4 was comparable for all three groups of rams and peak frequency was, as expected, consistently increased to 4 peaks per 6 hours. The increase in mean testosterone concentration (P $<$.05) in all three groups was due to an increase in testosterone baseline concentration and testosterone peak frequency.
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Hamudikuwanda, Humphrey. "Endocrine and metabolic mediators of dietary energy status and reproduction in dairy cows." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28770.

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Five experiments were undertaken to identify metabolites and hormones that could mediate the effect of dietary energy status on reproduction, particularly pulsatile secretion of luteinizing hormone (LH) postpartum dairy cows.
In the first two experiments, the concentration of progesterone (P4) in tailhead adipose tissue and plasma in 12 cows at different stages of pregnancy and lactation was determined as was P4 produced in vitro by explants of tailhead adipose tissue. Concentration of P4 in adipose tissue was correlated with that of plasma P4 near estrus and during the luteal phase of the estrous cycle, and P4 was released in vitro by fat mobilization.
In the third and fourth experiments, blood was collected continuously for 16 h from four ovariectomized cows offered maintenance or restricted energy diets after priming with P4 or estradiol (E2) using a crossover experimental design. The results indicated that P4 released during body fat mobilization is minor and is not related to LH secretion. Dietary energy restriction influenced plasma LH concentration and pulse amplitude but the effect was modulated by P4 and E2 priming. Dietary energy restriction decreased glucose concentration but did not influence plasma non-esterified fatty acids (NEFA), cortisol, P4 and insulin levels. Cortisol was negatively related to LH pulse frequency. Glucose and insulin were positively and negatively correlated with LH pulse amplitude, respectively. Cortisol, NEFA and glucose jointly had a negative correlation with LH concentration.
In the fifth experiment, blood samples were collected daily for 60 d and every 10 min for 8 h on 18, 36 and 54 d postpartum from 24 cows (12 ovariectomized) fed low (1.4 Mcal/kg DM) (L) or high (1.7 Mcal/kg DM) (H) energy in a 2 x 2 factorial treatment design. LH pulse frequency was reduced at 18 d postpartum in ovariectomized cows, but not in intact cows, fed L. First postpartum ovulation occurred later in intact cows fed L compared to those fed H. Energy balance and plasma glucose concentration were lower, but plasma NEFA, $ beta$-hydroxybutyrate (BHB) and E2 concentrations higher, in cows fed L compared to those fed H. E2 concentration in intact cows fed L was elevated for a prolonged period prior to first ovulation. Diet had no influence on plasma P4 and insulin concentrations. Plasma E2 and BHB concentrations were positively correlated with LH pulse frequency in intact cows across diets and ovariectomized cows fed L, respectively. NEFA were negatively correlated with LH pulse amplitude in ovariectomized cows fed L. Glucose, NEFA and P4 were negatively, but BHB, E2 and insulin positively correlated, individually or in association, with LH concentration.
Overall, the results suggest that the effect of dietary energy status on LH patterns and timing of onset of postpartum ovulation is modulated by priming with or presence of ovarian steroids. The relationships of metabolites and hormones with LH patterns appear to change with dietary energy level, ovarian status and mutual associations among the metabolites and hormones. These parameters, especially glucose and BHB, may be potential mediators of the effect of dietary energy status on LH patterns. (Abstract shortened by UMI.)
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Cassidy, Carrie. "Further evidence that prostaglandin F2-alpha is the obligatory eicosanoid in porcine ovulation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0004/MQ44139.pdf.

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Ferasyi, Teuku Reza. "Mathematical model of the reproductive endocrine system in male sheep." University of Western Australia. School of Animal Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0080.

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[Truncated abstract] The activity of the reproductive endocrine axis is the result of interactions among many organs and tissues, particularly the hypothalamus, pituitary gland and gonad. However, it depends on more than the communication between anatomical structures because it is also affected by genotype, internal factors (e.g., metabolic inputs) and external factors (e.g., photoperiod, socio-sexual cues, stress, nutrition). This multifactorial complexity makes it difficult to use animal experimentation to investigate the pathways and mechanisms involved. Therefore, in this study, I have turned to mathematical modelling. The general hypothesis was that, by modelling the hormonal feedback loop that links the hypothalamus, pituitary gland and gonad, I would be able to discover the critical control points in this homeostatic system. This would allow me to inform and direct research into the processes that control reproduction, including inputs from environmental factors. My studies began with the development of a model of the negative feedback loop through which testosterone controls the secretion of pulses of gonadotrophin-releasing hormone (GnRH) by the hypothalamus. The model incorporated two critical factors: testosterone concentration and a time delay in the inhibition of the activity of the GnRH 'pulse generator' by testosterone. The general assumptions were: i) there are two positive feedforward processes (GnRH pulses stimulate LH pulses, and, in turn, LH pulses stimulate testosterone secretion); ii) testosterone exerts negative feedback that reduces the frequency of GnRH pulses. The model incorporated a group of equations that represent the GnRH pulse generator, through which the inhibitory effect of testosterone acted to reduce GnRH pulse frequency. Simulations were run with various values for the time delay in feedback and, as model development progressed, the simulations were extended to include combinations of time delays and levels of sensitivity of the GnRH pulse generator to inhibition by testosterone. The output of the simulations showed clearly that a time delay in negative feedback, as well as the concentration of testosterone, can greatly affect the frequency of GnRH pulses and the shape of the GnRH secretory profile. Importantly, the effect of the time delay depends on the sensitivity of the pulse generator to testosterone. In addition, the simulations suggested two additional components that might be involved in the control of the GnRH pulse generator: i) a delay in the rate of adaptation to a change in steroid feedback; and ii) a minimum pulse interval (maximum frequency). These studies iii therefore suggest that the regulation of the activity of the GnRH pulse generator, and thus the frequency and profile of GnRH and LH pulses, requires interactions among these four components. These interactions should be tested in animal experimentation. In the next stage, I extended the model so I could test whether the feedback delay might involve the process of aromatization in which testosterone is converted to oestradiol at brain level. ... This information can be used to direct future experimental studies that will help us to understand the factors that underlie the dynamic behaviour of the hypothalamic and pituitary systems that control reproduction.
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Cote, Fabienne. "Induction of prostaglandin endoperoxide synthase 2 in the follicles of equine chorionic gonadotropinhuman chorionic gonadotropin treated prepubertal gilts." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33741.

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Prostaglandin G/H synthase-2 (PGHS-2) is a key rate limiting enzyme in the prostaglandin (PG) biosynthetic pathway, and PG synthesis is required for ovulation in pigs. The objective of this study was to characterize the expression and regulation of PGHS-2 in porcine follicles prior to ovulation. The combination of equine chorionic gonadotropin (eCG; 750 IU) followed by human chorionic gonadotropin (hCG; 500 IU) 72 h later was used to induce ovulation in prepubertal gilts. Previous studies have shown that ovulation is generally induced between 40 and 44 h post-hCG in this model. Ovariectomies were performed at 0, 24, 30, 34 and 38 h post-hCG (n = 4 or 5 animals per time-point), and all follicles larger than 4 mm in diameter were isolated. The regulation of PGHS-1 and PGHS-2 proteins was studied by immunohistochemistry and Western blot analyses, whereas the regulation of PGHS-2 mRNA was studied by Northern blot. PG production was assessed by radioimmunoassay (RIA). (Abstract shortened by UMI.)
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Algire, James Edgar. "Prostaglandins in follicular development and ovulation in cattle." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61849.

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Matsuno, April Y. "Dietary glucose restriction, chronic exercise and litter size : effects on rat milk and mammary gland compositions." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27377.

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Glucose is a principle precursor for milk lactose and de novo synthesis of milk fat; therefore exercising during lactation could create competition for glucose between exercising muscle and lactating mammary gland. This study investigated the combined effects of maternal dietary glucose (20%, 40%, 60%), exercise (chronically exercised, sedentary) and litter size (8, 12 pups) on rat mammary gland composition, milk composition, milk yield and pup growth. Chronic exercise increased milk fat concentrations and an interaction between chronic exercise and 20% dietary glucose decreased milk lactose concentrations compared to 40% or 60% glucose diets. Restricting maternal dietary glucose also decreased milk fat concentrations and exercise decreased mammary fat. In addition, pups of dams fed the 40% glucose diet were heavier on lactation day 15 than pups of dams fed the 60% diet. These results suggest that competition for glucose occurs and that a 40% glucose maternal diet may be more appropriate for pup growth.
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Books on the topic "Rats – Reproduction – Endocrine aspects"

1

McKeown, Ronan Michael. The effect of immunization against an inhibin fragment on hormone concentrations and testicular function in rams. Dublin: University College Dublin, 1996.

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2

Agadzhani︠a︡n, N. A. Stress, adaptat︠s︡ii︠a︡, reproduktivnai︠a︡ sistema: Monografii︠a︡. Nizhniĭ Novgorod: Nizhegorodskai︠a︡ gos. medit︠s︡inskai︠a︡ akademii︠a︡, 2009.

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Fellows Conference (1992 Tucson, Ariz.). A Fellows Conference, Tucson, Arizona, January 17 and 18, 1992: Proceedings of a Fellows Conference. [Birmingham, Ala.]: American Fertility Society, 1992.

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A, Aruti͡u︡ni͡a︡n N., and Stepanov M. G, eds. Ėksperimentalʹnoe besplodie: Ėndokrinologicheskie aspekty. Sankt-Peterburg: "Nauka," S.-Peterburgskoe otd-nie, 1992.

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R, Olson Erik, and Naugle Jennifer E, eds. Endocrine and reproductive systems. Philadelphia: Elsevier Mosby, 2006.

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Carrell, Douglas T., and C. Matthew Peterson. Reproductive endocrinology and infertility: Integrating modern clinical and laboratory practice. New York: Springer, 2010.

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Shinkōkyoku, Japan Monbu Kagakushō Kenkyū. Naibunpitsu kakuran busshitsu ni yoru seishoku e no eikyō to sono sayō kikō ni kansuru kenkyū (Heisei 10--12-nendo): Seika hōkokusho. [Tokyo]: Monbu Kagakushō Kenkyū Shinkōkyoku, 2001.

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1924-, Iizuka Rihachi, Semm K. 1927-, and International Academy of Human Reproduction., eds. Human reproduction: Current status/future prospect : proceedings of the VIth World Congress on Human Reproduction, held in Tokyo, Japan, 25-30 October 1987. Amsterdam: Excerpta Medica, 1988.

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French-Israeli Symposium (1986 Tel Aviv, Israel). Reproduction in fish: Basic and applied aspects in endocrinology and genetics : proceedings of the French-Israeli Symposium, Tel-Aviv (Israel), 10-12 November 1986. Edited by Zohar Y and Breton B. Paris: Institut national de la recherche agronomique, 1988.

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Odent, Michel. The functions of the orgasms: The highways to transcendence. London: Pinter & Martin, 2009.

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Book chapters on the topic "Rats – Reproduction – Endocrine aspects"

1

Pivonello, Claudia, Cristina de Angelis, Francesco Garifalos, Rosario Pivonello, and Annamaria Colao. "Environmental Factors’ Interference in Endocrine Aspects of Male Reproduction." In Beyond Our Genes, 37–51. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-35213-4_3.

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Clemons, Gisela K. "Some Endocrine Aspects of Renal and Extrarenal Erythropoietin in Normoxic and Hypoxic Rats." In Molecular and Cellular Aspects of Erythropoietin and Erythropoiesis, 177–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-72652-1_15.

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Khanday, Sameena, Rayees Ahmad, and Guru Dutt Sharma. "Thermotolerance for Physiological and Endocrine Regulation of Embryo-Uterine Development." In Climate Change and Its Impact on Fertility, 135–57. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4480-8.ch007.

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Hyperthermia affects most aspects of reproductive performance in mammals by compromising the physiology of reproductive tract, through hormonal imbalance, disrupting the development and maturation of oocyte, causing embryonic mortality, abortion, growth retardation, and major developmental defects. Heat stress reduces the steroidogenic capacity of its theca and granulosa cells by altering the efficiency of follicular selection resulting in drop of luteinizing hormone and estradiol secretions from the dominant follicle in the plasma, reduced intensity, and duration of estrus expression. The mechanism for the developmental stage-dependent change in heat tolerance is considered to be the accumulation of antioxidants in embryos in response to heat-inducible production of reactive oxygen species. Morula or blastocysts can repair heat-induced misfolded or unfolded proteins or facilitate DNA damage induced apoptosis. Therefore, embryo transfer (ET) that can bypass the heat-sensitive stage could be a good solution to improve the conception rate under heat stress. However, further research is required to improve the reduction in pregnancy rates due to summer heat stress.
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Khanday, Sameena, Rayees Ahmad, and Guru Dutt Sharma. "Thermotolerance for Physiological and Endocrine Regulation of Embryo-Uterine Development." In Climate Change and Its Impact on Fertility, 135–57. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4480-8.ch007.

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Hyperthermia affects most aspects of reproductive performance in mammals by compromising the physiology of reproductive tract, through hormonal imbalance, disrupting the development and maturation of oocyte, causing embryonic mortality, abortion, growth retardation, and major developmental defects. Heat stress reduces the steroidogenic capacity of its theca and granulosa cells by altering the efficiency of follicular selection resulting in drop of luteinizing hormone and estradiol secretions from the dominant follicle in the plasma, reduced intensity, and duration of estrus expression. The mechanism for the developmental stage-dependent change in heat tolerance is considered to be the accumulation of antioxidants in embryos in response to heat-inducible production of reactive oxygen species. Morula or blastocysts can repair heat-induced misfolded or unfolded proteins or facilitate DNA damage induced apoptosis. Therefore, embryo transfer (ET) that can bypass the heat-sensitive stage could be a good solution to improve the conception rate under heat stress. However, further research is required to improve the reduction in pregnancy rates due to summer heat stress.
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5

Marcisz, Czeslaw, Tadeusz Slowik, Kazimierz Kita, Barbara Urbaniak-Lampart, Tomasz Jerzy Irzyniec, and Magda Marcisz-Orzel. "The Effect of Chronic Exposure to Carbendazyme on the Gonads and Reproduction of Rats." In BASIC/TRANSLATIONAL - Endocrine-Disrupting Chemicals, P1–104—P1–104. The Endocrine Society, 2011. http://dx.doi.org/10.1210/endo-meetings.2011.part1.p4.p1-104.

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"Reproduction and development." In Oxford Assess and Progress: Medical Sciences, edited by Jade Chow, John Patterson, Kathy Boursicot, and David Sales. Oxford University Press, 2012. http://dx.doi.org/10.1093/oso/9780199605071.003.0025.

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Reproduction and development are large topics, knowledge of which underpins several medical specialities including sexual health, fertility, gynaecology, urology, reproductive endocrinology, obstetrics, and neonatology. Doctors need to know the structure, function, and endocrine control of both male and female systems in order to diagnose and manage conditions specific to either male or female organs, as well as conditions such as impotence and infertility. Not surprisingly, the reproductive system is the only body system that shows major differences in both structure and function between males and females. However, sexual differences go beyond the primary sexual characteristics present at birth and the secondary sexual characteristics that emerge under the influence of sex hormones at puberty. Sexual dimorphism in some brain structures commences at an early age, and differences in the endocrine profiles of males and females produce characteristic changes in morphology, physiology, and behaviour that go beyond simple sexual dimorphism to affect many aspects of life, including sexual differences in susceptibility to disease and the longer life expectancy of women as compared to men that is seen around the world. Whether these differences, mainly beneficial to women, are because females are ‘biologically superior’ or because of a complex mix of genetic, behavioural, and social factors is a matter for discussion and research. Some knowledge of embryology is important to every medical student. As a minimum it provides explanations for the congenital malformations and their consequences that are encountered in many areas of clinical practice. Deeper knowledge will assist those seeking real insights into the structure of the human body. It is the study of embryological development and the knowledge of how each tissue type arises, how one tissue meets another, and how tissues move and change shape during development that explains the relations between tissues and organs in the adult human form. Achieving a full understanding of the dynamics of the formation of the body’s organs and tissues is demanding, but it can replace some of the rote learning of anatomical structures, familiar to many students, with a deeper understanding of form and function.
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Shum, M., S. Menard, A. Emond, T. Grenier-Larouche, C. Roberge, M.-F. Langlois, J.-P. Baillargeon, A. Hallberg, A. Carpentier, and N. Gallo-Payet. "Angiotensin II-AT2 Receptor Stimulation with the Selective Nonpeptide Agonist M24 (C21) Prevents Diet-Induced Insulin Resistance in Rats and Modulates Several Aspects of Adipocyte Physiology." In The Endocrine Society's 92nd Annual Meeting, June 19–22, 2010 - San Diego, P1–420—P1–420. Endocrine Society, 2010. http://dx.doi.org/10.1210/endo-meetings.2010.part1.p9.p1-420.

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