Academic literature on the topic 'Maturation hormonale'
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Journal articles on the topic "Maturation hormonale"
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de Almeida-Neto, Paulo Francisco, Paulo Moreira Silva Dantas, Vanessa Carla Monteiro Pinto, Tatianny de Macêdo Cesário, Nathália Monastirski Ribeiro Campos, Eduardo Estevan Santana, Dihogo Gama de Matos, Felipe J. Aidar, and Breno Guilherme de Araújo Tinoco Cabral. "Biological Maturation and Hormonal Markers, Relationship to Neuromotor Performance in Female Children." International Journal of Environmental Research and Public Health 17, no. 9 (May 8, 2020): 3277. http://dx.doi.org/10.3390/ijerph17093277.
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Background: Mechanisms that influence muscle strength can interfere with neuromotor performance and overall health, thus hormone markers and maturation can interact in this process. Objective: The present study aimed to verify the relationship of hormonal markers and biological maturation on neuromotor abilities in young people. Methods: This is a cross-sectional study with 44 female participants (11.5 ± 1.5 years). Hormones were analyzed biochemically. Skeletal and somatic maturation were analyzed using anthropometry. The muscular power of the upper and lower limbs, body speed with change of direction, and speed of the upper limbs were verified. Results: Bone age was correlated with hormonal markers (estradiol: r = 0.58; p = 0.0007), (testosterone: r = 0.51; p = 0.005). Peak growth velocity correlated with estradiol (r = 0.51; p = 0.004). The power of the lower limbs (estradiol: r = 0.52; p = 0.006; testosterone: r = 0.42; p = 0.03) and of the upper limbs (estradiol: r = 0.51; p = 0.007; testosterone: r = 0.42; p = 0.02) had a positive correlation with hormone levels and had similar results with maturation. The analysis by artificial neural networks indicated that the maturation can predict the neuromotor performance between 57.4% and 76%, while the hormonal markers showed a potential of more than 95% for the foreshadowing of the neuromotor performance of the upper limbs. Conclusion: It was possible to conclude that the hormones had a relationship with maturational development and bone age in female subjects.
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Chattergoon, Natasha N. "Thyroid hormone signaling and consequences for cardiac development." Journal of Endocrinology 242, no. 1 (July 2019): T145—T160. http://dx.doi.org/10.1530/joe-18-0704.
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The fetal heart undergoes its own growth and maturation stages all while supplying blood and nutrients to the growing fetus and its organs. Immature contractile cardiomyocytes proliferate to rapidly increase and establish cardiomyocyte endowment in the perinatal period. Maturational changes in cellular maturation, size and biochemical capabilities occur, and require, a changing hormonal environment as the fetus prepares itself for the transition to extrauterine life. Thyroid hormone has long been known to be important for neuronal development, but also for fetal size and survival. Fetal circulating 3,5,3′-triiodothyronine (T3) levels surge near term in mammals and are responsible for maturation of several organ systems, including the heart. Growth factors like insulin-like growth factor-1 stimulate proliferation of fetal cardiomyocytes, while thyroid hormone has been shown to inhibit proliferation and drive maturation of the cells. Several cell signaling pathways appear to be involved in this complicated and coordinated process. The aim of this review was to discuss the foundational studies of thyroid hormone physiology and the mechanisms responsible for its actions as we speculate on potential fetal programming effects for cardiovascular health.
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Almeida-Neto, Paulo Francisco de, Dihogo Gama de Matos, Vanessa Carla Monteiro Pinto, Paulo Moreira Silva Dantas, Tatianny de Macêdo Cesário, Luíz Felipe da Silva, Alexandre Bulhões-Correia, Felipe José Aidar, and Breno Guilherme de Araújo Tinôco Cabral. "Can the Neuromuscular Performance of Young Athletes Be Influenced by Hormone Levels and Different Stages of Puberty?" International Journal of Environmental Research and Public Health 17, no. 16 (August 5, 2020): 5637. http://dx.doi.org/10.3390/ijerph17165637.
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Background: Endocrine mechanisms can be a determining factor in the neuromuscular performance of young athletes. Objective: The objective of the present study was to relate maturational and hormonal markers to neuromuscular performance, as well as to verify whether young athletes with different testosterone levels show differences in muscle strength. Methods: The sample consisted of 37 young male Brazilian athletes (11.3 ± 0.94 years) who were members of a sports initiation project. Hormonal markers were analyzed biochemically by blood samples, and maturation markers by mathematical models based on anthropometry. Body composition was verified by tetrapolar bioimpedance. The performance of upper and lower limb strength and body speed were analyzed. Results: Hormonal and maturational markers were related to neuromuscular performance (p < 0.05). Young people with higher testosterone levels showed higher muscle strength (p < 0.05). Artificial neural networks showed that testosterone predicted the performance of upper limbs by 49%, and maturation by 60%. Maturation foreshadowed the performance of lower limbs by 30.3%. Conclusion: Biological maturation and hormonal levels can be related to neuromuscular performance, and young people with higher testosterone levels show superior muscle strength in relation to the others.
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Zenkevičs, Henriks, and Vija Vose. "Frog oocyte in vitro maturation test as a method to investigate Ni2+ toxicity." Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. 65, no. 1-2 (January 1, 2011): 29–31. http://dx.doi.org/10.2478/v10046-011-0015-3.
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Frog oocyte in vitro maturation test as a method to investigate Ni2+ toxicity The ability of gonadotropic hormone (GTH) of sturgeon fish Acipenser göldenstödti Br. to initiate a specific stimulatory effect on grass frog Rana temporaria L. oocytes, producing its in vitro maturation, was employed as a method to investigate the effect of nickel ion concentration on test oocytes in a highly sensitive test system, "Oocyte-GTH". Oocytes of four frogs with different hormone sensitivity were used in the investigation. It was shown that Ni2+ at a concentration of 0.1 mg/L produced a considerable stimulatory effect only in test frog oocytes with low hormonal sensitivity and maturation activity, while a Ni2+ concentration over 0.25 mg/L caused a significant decrease and produced even total blocking of the hormonal sensitivity and maturation ability of all oocytes, regardless of their initial hormonal sensitivity. The frog oocyte maturation test was shown to be a useful method to assess toxic effect of Ni2+ on water frog reproduction.
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Pinto, Vanessa Carla Monteiro, Petrus Gantois Massa Dias dos Santos, Rafaela Catherine Da Silva Cunha de Medeiros, Francisco Emílio Simplício Souza, Thaisys Blanc dos Santos Simões, Renata Poliane Nacer de Carvalho Dantas, and Breno Guilherme De Araújo Tinôco Cabral. "Maturational stages: comparison of growth and physical capacity indicators in adolescents." Journal of Human Growth and Development 28, no. 1 (March 12, 2018): 42. http://dx.doi.org/10.7322/jhgd.127411.
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Introduction: The identification of physical capacity is an important marker related to healthy behavior during childhood and adolescence, in which some factors appear to contribute to motor performance such as maturation and hormonal levels. Objective: To compare growth indicators, physical capacity and hormonal markers according to gender and maturational stage in adolescents. Methods: Eighty-nine adolescents of both genders aged 10-13 years participated in the study. Sexual maturation was evaluated using the Tanner’s self-evaluation method. Physical capacity (explosive strength of upper and lower limbs, upper limb velocity and agility) and hormonal markers (testosterone and estradiol) were evaluated through the chemiluminescence method. Results: In the comparison by gender, girls had higher weight (p = 0.023), height (p = 0.018) and fat percentage values (p = 0.001), while boys presented better motor performance for the explosive strength of upper limbs (p = 0.005) and lower limbs (p = 0.011), agility (0.018) and upper limb velocity (p = 0.014). Regarding maturational stage, boys did not present differences in any variable analyzed; (Stage V versus I), height (stage III, IV and V versus I) and upper limb explosive strength (stage III and IV versus I). Conclusion: Growth, weight and height, as well as explosive strength of upper limbs were higher in girls at more advanced maturational stages and appear to be gender dependent.
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Pinto, Vanessa Carla Monteiro, Petrus Gantois Massa Dias dos Santos, Matheus Peixoto Dantas, João Paulo De Freitas Araújo, Suzet De Araújo Tinoco Cabral, and Breno Guilherme De Araújo Tinoco Cabral. "Relationship between bone age, hormonal markers and physical capacity in adolescents." Journal of Human Growth and Development 27, no. 1 (April 13, 2017): 77. http://dx.doi.org/10.7322/jhgd.127658.
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Introduction: Physical capabilities are an important parameter of the functional development of adolescents, not only by chronological age but also by their maturational state, as individuals with the same chronological age can have different performance to their less mature counterparts. Objective: To compare and relate the physical capabilities and hormonal markers according to sex and maturity of adolescents. Method: The sample consisted of adolescents of both sexes, aged 10 to 14 years. We evaluated the maturity achieved by a predictive equation of skeletal age, physical capabilities (explosive power of upper and lower limbs, velocity of upper limbs and agility) and hormonal markers (testosterone and oestradiol) via chemiluminescence. Results: Females showed more advanced maturational status, higher weight, body height and oestradiol levels; males performed better in the explosive force of upper and lower limbs, upper limb speed, agility and testosterone levels. In the normal maturational state males showed greater skeletal age, body weight, body height, explosive strength of upper and lower limbs, and testosterone levels; the females in the normal maturational state had higher skeletal age, body weight, body height, explosive upper limb strength and oestradiol levels. In the male correlation analysis, bone age was related to the explosive strength of upper and lower limbs and testosterone; while bone age in females was related to explosive upper limb strength and oestradiol. Conclusion: It is concluded that maturation, testosterone and oestradiol levels play an important role in the physical aspects and performance of motor skills of adolescents, especially in upper limb force which was more related to the maturation obtained by skeletal age of males and females.
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Fui Fui, Ching, Gunzo Kawamura, Kazuhiko Anraku, Bensan Ali, Nabilah Zieha Sikh Mohamad, and Shigeharu Senoo. "Degeneration of the olfactory epithelium in the Anguilid eels by hormone treatment." Borneo Journal of Marine Science and Aquaculture (BJoMSA) 3, no. 2 (December 10, 2019): 48–51. http://dx.doi.org/10.51200/bjomsa.v3i2.1426.
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While the olfactory cue hypothesis has been proposed for spawning migration of silver eels, it has been shown that olfactory cells and associated mucus cells degenerate in male and female eels after hormonally induced sexual maturation. However, the degeneration of the olfactory organ could be a real event in the sequence of maturation, or may be an unnatural side effect of the hormone treatment itself. We morphologically and histologically examined the olfactory rosettes of hormone-untreated and hormone-treated (mixture of hCG and PG) giant mottled eel (Anguilla marmorata) and Japanese eel (A. japonica). The olfactory rosette from all the hormone-treated specimens significantly degenerated at various degeneration levels even in sexually immature specimens, indicating the side effect of the hormone-treatment. However, a sexually immature non-hormone treated female A. marmorata (87.4 cm TL, 199.4 g BW, at less advanced maturity) had slightly degenerated olfactory rosette. Further studies should focus on conducting natural degeneration of the olfactory rosette during the sexual maturation in tropical eels.
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Fui Fui, Ching, Gunzo Kawamura, Kazuhiko Anraku, Bensan Ali, Nabilah Zieha Sikh Mohamad, and Shigeharu Senoo. "Degeneration of the olfactory epithelium in the Anguilid eels by hormone treatment." Borneo Journal of Marine Science and Aquaculture (BJoMSA) 3, no. 2 (December 10, 2019): 48–51. http://dx.doi.org/10.51200/bjomsa.v3i2.1426.
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While the olfactory cue hypothesis has been proposed for spawning migration of silver eels, it has been shown that olfactory cells and associated mucus cells degenerate in male and female eels after hormonally induced sexual maturation. However, the degeneration of the olfactory organ could be a real event in the sequence of maturation, or may be an unnatural side effect of the hormone treatment itself. We morphologically and histologically examined the olfactory rosettes of hormone-untreated and hormone-treated (mixture of hCG and PG) giant mottled eel (Anguilla marmorata) and Japanese eel (A. japonica). The olfactory rosette from all the hormone-treated specimens significantly degenerated at various degeneration levels even in sexually immature specimens, indicating the side effect of the hormone-treatment. However, a sexually immature non-hormone treated female A. marmorata (87.4 cm TL, 199.4 g BW, at less advanced maturity) had slightly degenerated olfactory rosette. Further studies should focus on conducting natural degeneration of the olfactory rosette during the sexual maturation in tropical eels.
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Gupta, Neena, Vangipuram Dwarakanath, and Michel Baum. "Maturation of the Na+/H+ antiporter (NHE3) in the proximal tubule of the hypothyroid adrenalectomized rat." American Journal of Physiology-Renal Physiology 287, no. 3 (September 2004): F521—F527. http://dx.doi.org/10.1152/ajprenal.00005.2004.
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In previous studies examining the role of glucocorticoids and thyroid hormone on the maturation of the Na+/H+ antiporter (NHE3), we found attenuation in the maturational increase in proximal tubule apical Na+/H+ antiporter activity but no change in NHE3 mRNA abundance in either glucocorticoid-deficient or hypothyroid rats. In addition, prevention of the maturational increase in either hormone failed to totally prevent the maturational increase in Na+/H+ antiporter activity. We hypothesized that one hormone played a compensatory role when the other was deficient. The present study examined whether combined deficiency of thyroid and glucocorticoid hormones would completely prevent the maturation of the Na+/H+ antiporter. Adrenalectomy was performed in 9-day-old hypothyroid Sprague-Dawley rats, a time before the normal postnatal maturational increase in these hormones occurs. Nine- and 30-day-old adrenalectomized (ADX), hypothyroid rats had comparable NHE3 mRNA abundance, which was 5- to 10-fold less than 30-day-old ADX, hypothyroid rats that received corticosterone-thyroxine replacement and 30-day-old sham control rats ( P < 0.05). Brush-border membrane NHE3 protein abundance was comparable in 9- and 30-day-old ADX, hypothyroid groups and ∼20-fold lower than both the 30-day replacement and 30-day sham groups ( P < 0.05). Similarly, the replacement and sham groups had higher sodium-dependent proton secretion than 9- and 30-day-old ADX, hypothyroid groups ( P < 0.05). We conclude that combined deficiency of both hormones totally prevents the maturational increase in NHE3 mRNA and protein abundance and Na+/H+ antiporter activity.
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Wu, Xiufeng, Ramamani Arumugam, Ningning Zhang, and Mary M. Lee. "Androgen profiles during pubertal Leydig cell development in mice." REPRODUCTION 140, no. 1 (July 2010): 113–21. http://dx.doi.org/10.1530/rep-09-0349.
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Postnatal Leydig cell (LC) development in mice has been assumed empirically to resemble that of rats, which have characteristic hormonal profiles at well-defined maturational stages. To characterize the changes in LC function and gene expression in mice, we examined reproductive hormone expression from birth to 180 days, and quantified in vivo and in vitro production of androgens during sexual maturation. Although the overall plasma androgen and LH profiles from birth through puberty were comparable to that of rats, the timing of developmental changes in androgen production and steroidogenic capacity of isolated LCs differed. In mice, onset of androgen biosynthetic capacity, distinguished by an acute rise in androstenedione and testosterone production and an increased expression of the steroidogenic enzymes, cytochrome P450 cholesterol side-chain cleavage enzyme and 17α-hydroxylase, occurred at day 24 (d24) rather than at d21 as reported in rats. Moreover, in contrast to persistently high testosterone production by pubertal and adult rat LCs, testosterone production was maximal at d45 in mice, and then declined in mature LCs. The murine LCs also respond more robustly to LH stimulation, with a greater increment in LH-stimulated testosterone production. Collectively, these data suggest that the mouse LC lineage has a delayed onset, and that it has an accelerated pace of maturation compared with the rat LC lineage. Across comparable maturational stages, LCs exhibit species-specific developmental changes in enzyme expression and capacity for androgen production. Our results demonstrate distinct differences in LC differentiation between mice and rats, and provide informative data for assessing reproductive phenotypes of recombinant mouse models.
Dissertations / Theses on the topic "Maturation hormonale"
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Pham, Viet-Laï. "Aminopeptidase B : modélisation moléculaire et étude du site actif par mutagenèse dirigée." Paris 6, 2007. http://www.theses.fr/2007PA066546.
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L’aminopeptidase B (Ap-B ; EC 3. 4. 11. 6) hydrolyse les acides aminés basiques en N-terminal de peptides et est impliquée dans la maturation d’hormones et probablement de neuropeptides selon un mécanisme original récemment mis en évidence. À ce jour, un seul de ses substrats physiologiques a été identifié, le glucagon qui, de par l’action successive de la NRD convertase puis de l’Ap-B, est transformé en miniglucagon. Ces deux hormones participent à la régulation de l’homéostasie du glucose chez les Mammifères. Une autre particularité de l’Ap-B est de présenter, in vitro, une activité résiduelle de type e��poxyde hydrolase, capable d’hydrolyser le leucotriène A4 (LTA4) en leucotriène B4, un médiateur lipidique de l’inflammation. A l’inverse, son plus proche parent phylogénétique, la Leucotriène A4 Hydrolase (LTA4H ; EC 3. 3. 2. 6) possède, en plus de son activité époxyde hydrolase, une activité aminopeptidase toutefois moins spécifique. Une analyse structurale et fonctionnelle de l’Ap-B est nécessaire pour mieux comprendre les mécanismes catalytiques de l’enzyme et pour parvenir à la conception d’inhibiteurs spécifiques, dont l’utilisation devrait nous éclairer sur l’ensemble de ses fonctions in vivo. Nous avons mis au point un système d’expression et de purification de l’Ap-B chez E. Coli avant d’entreprendre une analyse fonctionnelle par mutagenèse dirigée d’un certain nombre de résidus potentiellement impliqués dans l’activité de l’enzyme. Ces acides aminés ont été identifiés par alignement des séquences des protéines de la famille M1 à laquelle appartiennent l’Ap-B et la LTA4H. Cette étude a, par ailleurs, permis d’identifier 3 sous-familles distinctes d’aminopeptidases. Cette famille M1 est caractérisée par la présence d’un motif de fixation du cation Zn2+ de type HEXXHX18E. Les mutations des résidus de ce motif conduisent à une perte totale de l’activité de l’Ap-B, confirmant ainsi le rôle essentiel de ces résidus dans le mécanisme catalytique. La famille M1 est également caractérisée par la présence d’un second motif consensus (GXMEN). Nous avons également muté l’ensemble des résidus de ce second motif. Si les mutations des acides aminés M, E et N conduisent à une perte de l’activité, les mutations du résidu G en sérine ou proline donnent naissance à deux protéines actives. Le mutant G298S a des propriétés proches de l’enzyme sauvage, tandis que le mutant G298P présente une modification de sa spécificité de substrat (clivage de R, K, P et A), de son profil d’inhibition et de son activité en présence d’ions Cl-. L’analyse de ces mutants par dichroïsme circulaire et spectrométrie de fluorescence montre que les structures globales de ces enzymes ne semblent pas perturbées. Dix autres acides aminés ont également été mutés et leur étude fonctionnelle est en cours. Les similitudes structurales et fonctionnelles de l’Ap-B et de la LTA4H dont la structure 3D est connue, nous a permis de construire un modèle moléculaire de la structure de l’Ap-B. Ce modèle a été utilisé pour, d’une part, essayer de comprendre le rôle du résidu Glycine du motif GXMEN et, d’autre part, pour mettre en évidence un certain nombre de différences entre l’Ap-B et la LTA4H, en particulier au niveau du site actif et des propriétés potentielles d’interactions protéine-protéines de l’Ap-B. En parallèle, nous avons mis au point un second système d’expression et de purification de l’Ap-B à partir d’un vecteur baculovirus et de cellules d’insectes. Ce système nous permet d’obtenir une quantité suffisante d’enzyme pour mettre au point les conditions de cristallogenèse de la protéineAminopeptidase B (Ap-B ; EC 3. 4. 11. 6) cleaves basic residues at the N-terminus of peptides and participates in hormone and neuropeptide processing through an original mechanism recently described. The only known physiological substrate of Ap-B is the glucagon, which is processed into miniglucagon by NRD convertase and Ap-B. In mammals, these hormones are involved in the regulation of glucose homeostasis. One second characteristic of Ap-B is that the enzyme exhibits, in vitro, a residual ability to hydrolyze leukotriene A4 (LTA4) into the pro-inflammatory lipid mediator leukotriene B4. Inversely, LTA4 hydrolase (LTA4H ; EC 3. 3. 2. 6), the closest homologous protein of Ap-B, possesses, besides an epoxyde hydrolase activity, an aminopeptidase activity of broader specificity. Both proteins belong to the M1 family of Zn2+-aminopeptidases. A structure-function analysis is needed for a detailed understanding of the enzymatic mechanisms of Ap-B and to aid in the design of inhibitors, which could be used to determine its whole in vivo functions. In order to carry out a functional analysis by site-directed mutagenesis, we developed an expression system and a purification procedure of Ap-B using E. Coli. Amino acid residues potentially involved in the aminopeptidase activity are identified using alignments of primary structures of proteins from the M1 family. This study allowed us to identify 3 distinct M1 sub-families. This M1 family is characterized by the presence of a HEXXHXn=18E Zn2+- binding motif. Mutations of these residues lead to a total loss of activity and confirm their essential roles in catalysis. The major part of the M1 family members (Ap-B, LTA4H,…) constitutes the main sub-family and possesses a second consensus motif (GXMEN). Mutations of the M, E or N residues also lead to a total loss of aminopeptidase activity. Surprisingly, replacement of the conserved glycine into a serine or a proline created two new active enzymes. The G298S mutant exhibits properties similar to the wild type enzyme, whereas the G298P mutant shows a modification of its substrate specificity (recognizing R, K, P and A), its inhibition profile and its behavior towards Cl-. Fluorescence spectroscopy and circular dichroïsm analyses did not show any fundamental modification in the mutant structures. Ten other residues were mutated in the Ap-B primary structure and their functional studies are in progress. The sequence and catalytic similarities shared between Ap-B and LTA4H and the determination of the X-ray structure of LTA4H led us to build a 3D structural model of Ap-B. This model was used, on one hand, to better understand the enzymatic role of the glycine residue of the GXMEN motif and, on the other hand, to highlight functional differences between Ap-B and LTA4H, particularly at the level of their active site and of their proteinprotein interaction properties. In parallel, we also developed a second system of expression and purification of Ap-B using baculovirus and insect cells. This system allows us to purify a sufficient amount of protein for crystallogenesis assays
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Baribault, Hélène. "Régulation hormonale de la prolifération, de la maturation et de l'expression des cytokératines des cultures d'hépatocytes en voie de différenciation." Doctoral thesis, Université Laval, 1986. http://hdl.handle.net/20.500.11794/33558.
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La régulation hormonale de la prolifération et de la différenciation cellulaire peut varier selon les types cellulaires ainsi que leur degré de transformation. Le but principal de ce travail était d'élaborer un système de cellules épithéliales en culture primaire et d'étudier les mécanismes de la régulation hormonale de leur croissance en fonction de leur capacité à exprimer certaines fonctions foetales et différenciées. L'élaboration d'un système de culture d'hépatocytes de rat nouveau-né, en voie de différenciation a permis d'étudier la régulation hormonale de la prolifération et de la différenciation des hépatocytes. Les hépatocytes de rat de 14 jours représentent une population de cellules diploïdes, qui sont synchronisées dans la phase Gi du cycle cellulaire au moment de l'isolement et qui expriment encore des fonctions immatures telle la production d' a-foetoprotéine. Suite à une stimulation par l'EGF et l'insuline ou l'EGF et le glucagon, les hépatocytes de rat de 14 jours ont une plus grande capacité à proliférer que les hépatocytes de rat adulte. Les seuls critères qui distinguent les populations d'hépatocytes de rats nouveau-né et adulte sont leur niveau de ploidie et leur degré de maturation. L'addition de dexaméthasone en présence de ces facteurs de croissance amènent une inhibition sélective de la production d'AFP par rapport à l'albumine, un changement généralement associé à une maturation des hépatocytes. De plus, la dexaméthasone induit une inhibition de la prolifération des hépatocytes en présence de EGF et de glucagon et non en présence d'EGF et d'insuline. Ces résultats mettent en évidence qu'il existe deux sentiers distincts par lesquels l'EGF peut être complémenté pour induire la prolifération des hépatocytes et que la dexaméthasone n'exerce un effet que sur celui utilisé par le glucagon. De plus, la prolifération et la maturation des hépatocytes peuvent être régulées de façon indépendante ou coordonnée. La dexaméthasone est le seul facteur parmi les facteurs testés capable d'induire une maturation des hépatocytes "in vitro". L'addition de DM50 ou de phénobarbital inhibe la prolifération des hépatocytes et permet de maintenir la production d ' -foetoprotéine ainsi que d'albumine. Parmi les événements induits précocement dans la phase préréplicative suite à une stimulation hormonale, plusieurs changements s'effectuent dans la synthèse, l'organisation et la phosphorylation des cytokératines. En effet, 1'addition d1 EGF induit une augmentation dans la phosphorylation de la cytokératine A sur le groupement tyrosine. Des analyses en immunofluorescence à l'aide d'anticorps monoclonaux dirigés spécifiquement contre les cytokératines A et D, anti-CK55 et anti-CK49 respectivement montrent que ce changement dans l'état de phosphorylation de la cytokératine A est associée à une réorganisation des filaments de cytokératines constituées de ces deux cytokératines A et D. D'autre part, la dexaméthasone induit une synthèse préférentielle des deux cytokératines majeures des hépatocytes, les cytokératines A et D. L'EGF n'influence pas cette réponse induite par la dexaméthasone. Cette néosynthèse préférentielle est associée à une inhibition sélective de la production d'a-foetoprotéine par rapport à l'albumine. Ces résultats montrent que les cytokératines sont vraisemblablement impliquées dans les réponses cellulaires induites par l'EGF et la néosynthèse de ces protéines est associée au programme de différenciation des hépatocytes.Montréal Trigonix inc. 2018
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Ebiou, Jean-Claude. "Le rôle biologique de la thyrotropin-releasing hormone (TRH) dans le pancréas endocrine." Paris 7, 1992. http://www.theses.fr/1992PA077056.
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L'objectif de ce travail est la recherche du rôle biologique de la TRH pancréatique. La TRH a été initialement isolée de l'hypothalamus et caractérisée comme pGlu-His-ProNH₂. Elle a ensuite été détectée dans le pancréas endocrine désigne comme deuxième site de synthèse du peptide. La TRH est synthétisée à partir d'un précurseur de haut poids moléculaire. La maturation complète de celui-ci génèrerait 5 molécules de TRH, et 7 peptides de connexion. Nous avons montré que la TRH secrétée par le pancréas a les mêmes caractéristiques chromatographiques que le peptide synthétique. La sécrétion de la TRH pendant le développement est stimulé par le glucose et l'arginine, tandis que ces mêmes secretagogues inhibent la sécrétion chez l'adulte. Fait intéressant, la sécrétion de la TRH augmente avec l’âge, en dépit de la chute des contenus pancréatiques. Nous avons caractérise deux peptides de connexion de la prepro-TRH: prepro-TRH160-169 et prepro-TRH178-199, dans des ilots de Langerhans, et le prepro-TRH178-199 dans le milieu de sécrétion. Concernant le rôle biologique de la TRH pancréatique, nous avons montré que: la TRH exogène stimule la sécrétion basale du glucagon; l'immunoneutralisation de la TRH endogène secrétée par l'anticorps anti-TRH inhibe significativement la sécrétion du glucagon induite par l'arginine, la sécrétion de somatostatine est légèrement inhibée. Sur une fistule pancréatique, la TRH inhibe la sécrétion exocrine des protéines, bicarbonates, et du sodium. Les résultats préliminaires sur les cellules acinaires indiquent une absence d'effet TRH. L'effet TRH, observe in vivo, serait medié par le système nerveux central. Au cours du développement, la TRH n'a pas d'effet sur les secrétions d'insuline et glucagon. Nous pensons qu'elle agirait sur le processus de prolifération des cellules insulaires. La TRH stimule la sécrétion du glucagon des cellules alpha. Il serait intéressant de rechercher l'action biologique des deux peptides de connexion. La détermination du mécanisme d'action de la TRH pancréatique implique la caractérisation des sites de liaison spécifiques. Ce travail a été publié dans: Endocrinology 1992, 130(3):1371-1379; Endocrinology 1992, 131(2) (à paraitre en aout); prostate tumeurs 1991, (7):9-10 et 1992(9):6-7.
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Puccio, François. "Influence de l'hydrocortisone, de l'egf, de la bombesine et du grf sur la proliferation cellulaire et la maturation du tractus gastrointestinal et du pancreas chez le jeune rat non sevre." Paris 6, 1988. http://www.theses.fr/1988PA066497.
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Liu, Mingchun. "Functional characterization of Sl-ERF.B3, a member of the large multi-gene family of Ethylene Response Factor in tomato (Solanum lycopersicum)." Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0089/document.
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Les derniers acteurs de la voie de signalisation à l’éthylène sont des facteurs de transcription appelés ERF (Ethylene Response Factors). La connaissance de leur rôle spécifique dans la régulation des processus développementaux dépendant de l’éthylène reste limitée. Les travaux présentés dans la thèse concernent la caractérisation fonctionnelle du gène Sl-ERF.B3, un membre de cette grande famille de régulateurs transcriptonnels dans la tomate (Solanum lycopersicum). Utilisant une stratégie répresseur dominant ; il est montré en particulier que ce gène intervient dans la mise en place de la réponse à l’éthylène et dans le contrôle de la maturation du fruit. L’expression d’une construction ERF.B3-SRDX, une version chimérique de Sl-ERF.B3 fusionné à un domaine répresseur de type EAR, entraine des phénotypes pléotropiques aussi bien dans la signalisation de l’éthylène que dans le développement des parties végétatives et des organes reproducteurs. Ainsi, une altération de la triple réponse à l’éthylène est constatée chez les lignées transgéniques et au stade adulte, les plantes présentent des phénotypes d’épinastie des feuilles, de sénescence prématurée des fleurs et d’abscission accélérée des fruits. L’ensemble de ces observations est corrélée avec une modification de l’expression de gènes impliqués dans la biosynthèse et la réponse à l’éthylène. Ces données suggèrent que ERF.B3 intervient dans un mécanisme de rétro-control de la réponse à l’éthylène en agissant à la fois sur les gènes de biosynthèse et de signalisation de l’hormone. Au niveau du fruit, la sur-expression d’ERF.B3-SRDX entraine une modification du processus de maturation avec un retard notable de l’avènement de l’acquisition de la compétence à murir. Cependant, une fois la maturation initiée, elle s’accompagne d’une forte production d’éthylène et d’une accélération du ramollissement du fruit. A l’inverse, l’accumulation de pigment est inhibée par altération de la voie de biosynthèse des caroténoïdes. Ces données phénotypiques sont corrélées avec le niveau d’expression des gènes clés impliqués dans ces processus. Les résultats indiquent que dans les lignées transgéniques, il y a découplage de certaines caractéristiques de la maturation du fruit et permettent de mettre en lumière le rôle d’ERF.B3 dans la régulation des processus de développement dépendant de l’éthylène chez la tomateEthylene Response Factors (ERFs) are known to be the last transcription factors of the ethylene transduction pathway. Their specific role in ethylene-dependent developmental processes remains poorly understood. This work demonstrated a specific role of Sl- ERF.B3, a member of the ERF gene family in tomato (Solanum lycopersicum), in mediating ethylene response and fruit ripening through a dominant repressor strategy. ERF.B3-SRDX dominant repressor etiolated seedlings displayed partial constitutive ethylene-response in the absence of ethylene and adult plants exhibited typical ethylenerelated alterations such as leaf epinasty, premature flower senescence and accelerated fruit abscission. The multiple symptoms related to enhanced ethylene sensitivity correlate with the altered expression of ethylene biosynthesis and signaling genes, suggesting the involvement of Sl-ERF.B3 in a feedback mechanism regulating components of ethylene production and response. In addition, over-expression of ERF.B3-SRDX in tomato results in alterations in both fruit morphology and ripening process. The attainment of competence to ripen is dramatically delayed in ERF.B3-SRDX fruits but once ripening proceeds it is associated with high climacteric ethylene production and enhanced fruit softening while pigment accumulation is strongly reduced. Moreover, a number of genes involved in the fruit ripening process showed expression pattern deviating from that of wild type. These data suggest a putative role of Sl-ERF.B3 in the transcriptional network underlying the ripening process and uncover a mean for uncoupling some of the main features of fruit ripening such as fruit softening and pigment accumulation. Overall, the study highlighted the importance of an ERF gene in ethylene-mediated developmental processes such as plant growth and fruit ripening
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Martin, Niall M. B. "Protein turnover in Salmonids : sexual maturation and hormonal control." Thesis, University of Aberdeen, 1990. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU548688.
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Aspects of tissue protein metabolism were studied in different groups of Atlantic salmon (Salmo salar). Firstly, 2 groups of sea water salmon were fasted for 3 and 5 days, prior to the measurement of tissue fractional rates of protein synthesis (ks, %day), using the method of 3H-phenylalanine flooding. The sensitivity of liver and gill to a short-term fast was indicated by their reduced rates of ks, while in other tissues such as ventricle, stomach and red muscle protein synthesis was unaffected. Both liver and gill are tissues which show the greatest capacities to synthesise protein, expressed by their high RNA contents. The response of tissue protein metabolism to sexual maturation was investigated in 2 groups of salmon undergoing river migration, tissues were analysed in both July salmon (sexually maturing) and in more mature October salmon. White muscle contributed most of the amino acids required during maturation, denoted by the high loss of protein and RNA from the flesh of the salmon by October. Red muscle, gill and ventricle were tissues which were protected during maturation, showing only slight changes in rates of protein metabolism. Liver, stomach and ovary on the other hand increased their RNA and protein contents, and showed increased rates of protein synthesis. The liver however, displayed a greater increase in its RNA concentration than protein i.e. the liver by October had increased its capacity to produce large amounts of export proteins. Despite the overall loss by stomach and other visceral tissues of protein and RNA, the stomach by October showed a dramatic 5-6 fold increase in its rate of protein synthesis. It was concluded that smooth muscle may have a particular role or function in the sexually mature fish. Factors controlling these in vivo changes in protein synthesis were investigated using rainbow trout (Oncorhynchus mykiss) isolated hepatocytes and a smooth muscle preparation in vitro . Anabolic actions on hepatocyte protein synthesis were exhibited by insulin, thyroxine and in the absence of fetal calf serum by triiodothyronine. The synthetic glucocorticoid, dexamethasone, unlike its actions in muscle, also exhibited an anabolic action on hepatocytes, by raising RNA and protein levels in cells from immature fish, while increasing protein synthesis rates in liver cells of sexually mature fish. Estradiol, like dexamethasone, stimulated rates of protein synthesis over 24 hours. However, hydroxyprogesterone caused no change in protein synthesis and decreased the effect of estradiol. Estradiol also increased protein synthesis rates in smooth muscle by some 30%. However, hydroxyprogesterone, as in liver cells, caused no stimulation of protein synthesis and again decreased the estradiol stimulated ks. It was proposed that estradiol is one of the factors involved in increasing the ks in the stomach of the sexually maturing salmon, while progesterone regulates the action of estradiol towards the end of sexual maturation, when such an effect of estradiol on liver and smooth muscle ks is unnecessary.
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Bussieres, Laurence. "Etude de la na-k-atpase renale par cytochimie quantitative." Paris 6, 1987. http://www.theses.fr/1987PA066289.
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Taranger, Geir Lasse. "Sexual maturation in Atlantic salmon, Salmo salar L.; aspects of environmental and hormonal control /." Online version, 1993. http://bibpurl.oclc.org/web/32827.
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Benedet, Perea Susana. "Growth hormone and somatolactin function during sexual maturation of female Atlantic salmon /." Göteborg : Göteborg University, Department of Zoology/Zoophysiology, 2008. http://gupea.ub.gu.se/dspace/bitstream/2077/18305/4/gupea_2077_18305_4.pdf.
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Pursell, Natalie W. "Hsp90-Mediated Maturation of Kinases and Nuclear Steroid Hormone Receptors: A Dissertation." eScholarship@UMMS, 2011. https://escholarship.umassmed.edu/gsbs_diss/535.
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Among heat shock proteins, Hsp90 is unusual because it is not required for the proper folding of most cellular proteins but rather is disproportionally linked to the activation of signal transduction proteins including over forty kinases and many steroid hormone receptors. Mutated forms of many Hsp90 clients are causative agents in cancer, making Hsp90 a promising pharmacological target. Many small molecular inhibitors have been identified that competitively bind to the ATP binding site of Hsp90, some of which are in clinical trials as anticancer agents. Although the activation of kinase and hormone receptor clients by Hsp90 and its co-chaperones has been extensively studied, the molecular mechanism of client protein activation is poorly understood.
Hsp90 is a dimeric chaperone containing three domains: the N-terminal (N) and middle (M) domains contribute directly to ATP binding and hydrolysis and the C-terminal (C) domain mediates dimerization. At physiological concentration, Hsp90 predominantly forms dimers, but the possibility that full-length monomers might also function in cells has not been tested. In Chapter 3, we used a single-chain strategy to design a full-length Hsp90 monomer (NMCC). The resulting construct was predominantly monomeric at physiological concentration and did not function to support yeast viability as the sole Hsp90. NMCC Hsp90 was also defective at ATP hydrolysis and the activation of kinase and steroid hormone receptor clients in yeast cells. The ability to support yeast growth was rescued by the addition of a coiled-coil dimerization domain, indicating that the parental single-chain construct is functionally defective because it is monomeric.
After finding that a full-length Hsp90 monomer containing only one ATPase site was unable to support yeast viability or activate Hsp90 clients, we set out to further explore the role of ATPase activity in client protein activation. Approximately 10 % of the yeast proteome binds to Hsp90 making it important to study Hsp90 function in the cellular environment where all binding partners are present. In Chapter 4, we observed that co-expression of different Hsp90 subunits in Saccharomyces cerevisiae caused unpredictable synthetic growth defects due to cross-dimerization. We engineered super-stabilized Hsp90 dimers that resisted cross-dimerization with endogenous Hsp90 and alleviated the synthetic growth defect. We utilized these super-stabilized dimers to analyze the ability of ATPase mutant homodimers to activate known Hsp90 client proteins in yeast cells. We found that ATP binding and hydrolysis by Hsp90 are both required for the efficient maturation of the glucocorticoid hormone receptor (GR) and v-src confirming the critical role of ATP hydrolysis in the maturation of steroid hormone receptors and kinases in vivo.
In addition to its role in the activation of signal transduction client proteins, Hsp90 has been shown to suppress the in vitro aggregation of numerous hard-to-fold proteins. In Chapter 5, we examine the role of charge in Hsp90 anti-aggregation activity. The charge on Hsp90 is largely concentrated in two highly acidic regions. We found that deletion of both charge-rich regions dramatically impaired Hsp90 anti-aggregation activity. Addition of an acid-rich region with a distinct amino acid sequence to our double-deleted Hsp90 construct rescued the anti-aggregation activity of Hsp90 indicating that the net charge contributes to its anti-aggregation activity.
The in vitro anti-aggregation activity of Hsp90 studied in Chapter 5 occurs in the absence of ATP. However, all of the biologically important functions of Hsp90 in cells identified to date, including the maturation of kinases and nuclear steroid hormone receptors, clearly require ATP hydrolysis. Why does Hsp90 robustly hinder the aggregation of hard-to-fold proteins without ATP in vitro, but in vivo uses ATP hydrolysis for all of its essential functions? By utilizing separation of function Hsp90 variants (that specifically lack in vitro anti-aggregation activity) we have begun to address this question. We find that anti-aggregation deficient Hsp90 is unable to support yeast growth under stressful conditions, potentially due to reduced cellular expression. Interestingly, the ATP-independent anti-aggregation activity of Hsp90 has no measureable impact on cellular function. Thus, hindering the aggregation of most hard-to- fold proteins by Hsp90 (independent of ATP hydrolysis) does not appear to be important for cell function. These results suggest a cellular model where the Hsp40/60/70 machinery is responsible for hindering the aggregation of most hard-to-fold proteins while Hsp90 assists in the maturation of a select set of clients in an ATP-dependent fashion, potentially aided by its inherent anti-aggregation properties.
Books on the topic "Maturation hormonale"
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Jürimäe, Jaak. Hormones and training. Edited by Neil Armstrong and Willem van Mechelen. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198757672.003.0033.
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Physical exercise regulates energy balance and is important to growth and maturation. These processes are regulated by the endocrine system. Endocrine mechanisms in the response to sport training include growth hormone-insulin-like growth factor-1 (GH-IGF-1), hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal axes, and peripheral markers of energy homeostasis. Physical performance is associated with anabolic adaptations of the GH-IGF-1 system in child athletes alongside spontaneous growth, while heavy training does not affect basal testosterone levels. In female adolescent athletes, the major factor altering reproductive hormone secretion is energy deficiency, rather than exercise stress or increase in exercise energy expenditure. Ghrelin is another indicator of energy imbalance across the menstrual cycle. Pubertal onset decreases ghrelin, and leptin levels are reduced and may remain unchanged between prepuberty and maturation in athletes. To better understand the influence of high training load on hormonal markers responsible for overall growth and energy homeostasis, growing athletes should be monitored often.
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Jürimäe, Toivo, and Jaak Jürimäe. Hormonal responses and adaptations. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199232482.003.0038.
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This chapter focuses on the available information about the effects of acute exercise and chronic training on the secretion of different growth and energy balance related hormones at different stages of linear growth and sexual maturation throughout childhood. In addition, the role of recently discovered hormones, such as leptin and ghrelin, that assist in regulating energy balance as well as somatic and pubertal growth in children are discussed.
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(Editor), M. B. Ranke, and G. Gilli (Editor), eds. Growth Standards, Bone Maturation and Idiopathic Short Stature (Journal - Hormone Research , Vol 45, Suppl. 2). S. Karger AG (Switzerland), 1996.
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Nikravan, Sara, and Frederick Mihm. Pathophysiology and management of functional endocrine tumours in the critically ill. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0264.
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Thyroid hormones act on most tissues via nuclear T3 receptors. Thyroid hormones stimulate oxygen consumption and heat production, influence cell growth and maturation (central nervous system, bone), and modulate metabolism (carbohydrates, lipids, proteins, drugs). Treatment for presumed thyroid disease frequently has to be initiated before the results of diagnostic tests are available. Treatment of hyperthyroidism should result in the reduction of serum thyroid hormone levels and their action on peripheral tissues with concurrent treatment of the precipitating event. In severe hypothyroidism the choice of thyroid hormone (thyroxine or tri-iodothyronine), optimal dosing, and the route of administration remain controversial
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Falk, Bareket, and Raffy Dotan. Temperature regulation. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199232482.003.0023.
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This chapter outlines the physical and physiological changes that occur during growth and maturation and the possible effects these changes can have on the nature and effectiveness of thermoregulation. The physiological responses to heat stress are discussed in terms of metabolic, circulatory, hormonal, and sweating responses, changes in body temperature, and in terms of heat tolerance. Also discussed is hydration status, which can affect thermoregulatory effectiveness in the heat. The physiological response to cold stress is considered in terms of the metabolic and circulatory responses and their possible influence on the effectiveness of thermoregulation. The discussion does not outline the thermoregulatory response per se, but rather emphasizes the differences in that response between children and adults. Finally, child–adult differences in the acclimatization- and training-induced adaptations to thermal stress are discussed.
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Sisk, Cheryl L., and Russell D. Romeo. Coming of Age. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780195314373.001.0001.
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The purpose of this book is to explore the neurobiology and psychobiology underlying puberty and adolescence. It tells the story of how contemporary neuroscience has come to make significant contributions to the understanding of a developmental period that used to be the sole purview of developmental psychologists and pediatric endocrinologists. The authors presume the reader will have a general understanding of the basic principles of neuroscience and psychology and have written this book to serve as an appropriate text for an upper-level undergraduate seminar or graduate course designed to probe puberty and adolescence more deeply from a psychobiological perspective. Topics covered in specific chapters include timing and regulation of reproductive maturation (puberty), mechanisms of adolescent brain development in laboratory animals and humans, neural underpinnings of higher risk-taking and impulsive behavior in adolescents, hormonal programming of social behaviors during adolescence, and effects of stress and drugs on the adolescent brain. The book ends with the authors’ perspective on some of the big questions about the adolescent brain and behavior that remain to be answered.
Book chapters on the topic "Maturation hormonale"
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Ballard, Philip L. "Hormone Interactions." In Hormones and Lung Maturation, 322–45. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82483-8_10.
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Ballard, Philip L. "Antenatal Glucocorticoid Therapy: Hormone Concentrations." In Hormones and Lung Maturation, 173–96. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82483-8_6.
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Giles, W., and M. Agrez. "Metalloproteinases and Cervical Maturation." In Frontiers of Hormone Research, 269–78. Basel: KARGER, 2001. http://dx.doi.org/10.1159/000061032.
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Fisher, Delbert A., and Daniel H. Polk. "Maturation of Thyroid Hormone Actions." In Research in Congenital Hypothyroidism, 61–77. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4684-7580-7_5.
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Tata, Jamshed R., Tharappel C. James, Cheryl S. Watson, John L. Williams, and Alan P. Wolffe. "Hormonal Regulation and Expression of Vitellogenin Multigene Family." In Ciba Foundation Symposium 98 - Molecular Biology of Egg Maturation, 96–110. Chichester, UK: John Wiley & Sons, Ltd, 2008. http://dx.doi.org/10.1002/9780470720790.ch7.
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Ellissa Baskind, N., and Vinay Sharma. "Follicular Fluid Hormone Profiles in Natural Cycle IVF Patients During Follicular Phase." In Development of In Vitro Maturation for Human Oocytes, 105–28. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-53454-1_6.
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Giustina, Andrea, Paolo Desenzani, and Tiziano Scalvini. "Impact of Testosterone Replacement on the Maturation of the Growth Hormone—IGF-I Axis." In Sex-Steroid Interactions with Growth Hormone, 20–31. New York, NY: Springer New York, 1999. http://dx.doi.org/10.1007/978-1-4612-1546-2_3.
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Kumar, Rajesh, Dushyant Kumar Damle, and Bindu R. Pillai. "Hormonal Influence on Induced Maturation and Spawning in Striped Murrel, Channa striata." In Recent updates in molecular Endocrinology and Reproductive Physiology of Fish, 63–76. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8369-8_5.
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Alferez, F., and L. Zacarias. "Interaction Between Ethylene and Abscisic Acid in the Regulation of Citrus Fruit Maturation." In Biology and Biotechnology of the Plant Hormone Ethylene II, 183–84. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4453-7_30.
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Leshem, Y. Y., R. B. H. Wills, and V. V. Ku. "On Chloroplast Involvement and Ethylene and Nitric Oxide (NO•) Stoichiometry in Fruit Maturation." In Biology and Biotechnology of the Plant Hormone Ethylene II, 401–4. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4453-7_74.
Full textConference papers on the topic "Maturation hormonale"
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Brown, Mark R. "Ovary ecdysteroidogenic hormone and insulin-like peptide signaling convergently activate egg maturation in mosquitoes." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.93861.
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Sakurai, R., E. Shin, JS Torday, and VK Rehan. "Physiologic Vitamin D Hormone 1α,25(OH)2D3Has Spatial- and Temporal-Specific Effects during Perinatal Pulmonary Maturation." In American Thoracic Society 2009 International Conference, May 15-20, 2009 • San Diego, California. American Thoracic Society, 2009. http://dx.doi.org/10.1164/ajrccm-conference.2009.179.1_meetingabstracts.a2632.
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Ali, SM, K. Leitzel, M. Li, K. Udd, J. Wang, E. Sanchez, H. Chen, J. Berenson, and A. Lipton. "Abstract P1-02-10: Reduced serum B-cell maturation antigen levels predict poor outcome in metastatic breast cancer patients in a phase 3 randomized 2nd-line hormone therapy trial." In Abstracts: 2016 San Antonio Breast Cancer Symposium; December 6-10, 2016; San Antonio, Texas. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.sabcs16-p1-02-10.
Full textReports on the topic "Maturation hormonale"
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Yaron, Zvi, Abigail Elizur, Martin Schreibman, and Yonathan Zohar. Advancing Puberty in the Black Carp (Mylopharyngodon piceus) and the Striped Bass (Morone saxatilis). United States Department of Agriculture, January 2000. http://dx.doi.org/10.32747/2000.7695841.bard.
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Both the genes and cDNA sequences encoding the b-subunits of black carp LH and FSH were isolated, cloned and sequenced. Sequence analysis of the bcFSHb and LHb5'flanking regions revealed that the promoter region of both genes contains canonical TATA sequences, 30 bp and 17 bp upstream of the transcription start site of FSHb and LHb genes, respectively. In addition, they include several sequences of cis-acting motifs, required for inducible and tissue-specific transcriptional regulation: the gonadotropin-specific element (GSE), GnRH responsive element (GRE), half sites of estrogen and androgen response elements, cAMP response element, and AP1. Several methods have been employed by the Israeli team to purify the recombinant b subunits (EtOH precipitation, gel filtration and lentil lectin). While the final objective to produce pure recombinantGtH subunits has not yet been achieved, we have covered much ground towards this goal. The black carp ovary showed a gradual increase in both mass and oocyte diameter. First postvitellogenic oocytes were found in 5 yr old fish. At this age, the testes already contained spermatozoa. The circulating LH levels increased from 0.5 ng/ml in 4 yr old fish to >5ng/ml in 5 yr old fish. In vivo challenge experiments in black carp showed the initial LH response of the pituitary to GnRH in 4 yr old fish. The response was further augmented in 5 yr old fish. The increase in estradiol level in response to gonadotropic stimulation was first noted in 4 yr old fish but this response was much stronger in the following year. In vivo experiments on the FSHb and LHb mRNA levels in response to GnRH were carried out on common carp as a model for synchronom spawning cyprinids. These experiments showed the prevalence of FSHP in maturing fish while LHP mRNA was prevalent in mature fish, especially in females. The gonadal fat-pad was found to originate from the retroperitoneal mesoderm and not from the genital ridge, thus differing from that reported in certain amphibians This tissue possibly serves as the major source of sex steroids in the immature black carp. However, such a function is taken over by the developing gonads in 4 yr old fish. In the striped bass, we described the ontogeny of the neuro-endocrine parameters along the brain-pituitary-gonadal axis during the first four years of life, throughout gonadal development and the onset of puberty. We also described the responsiveness of the reproductive axis to long-term hormonal manipulations at various stages of gonadal development. Most males reached complete sexual maturity during the first year of life. Puberty was initiated during the third year of life in most females, but this first reproductive cycle did not lead to the acquisition of full sexual maturity. This finding indicates that more than one reproductive cycle may be required before adulthood is reached. Out of the three native GnRHs present in striped bass, only sbGnRH and cGnRH II increased concomitantly with the progress of gonadal development and the onset of puberty. This finding, together with data on GtH synthesis and release, suggests that while sbGnRH and cGnRH II may be involved in the regulation of puberty in striped bass, these neuropeptides are not limiting factors to the onset of puberty. Plasma LH levels remained low in all fish, suggesting that LH plays only a minor role in early gonadal development. This hypothesis was further supported by the finding that experimentally elevated plasma LH levels did not result in the induction of complete ovarian and testicular development. The acquisition of complete puberty in 4 yr old females was associated with a rise in the mRNA levels of all GtH subunit genes, including a 218-fold increase in the mRNA levels of bFSH. mRNA levels of the a and PLH subunits increased only 11- and 8-fold, respectively. Although data on plasma FSH levels are unavailable, the dramatic increase in bFSH mRNA suggests a pivotal role for this hormone in regulating the onset and completion of puberty in striped bass. The hormonal regulation of the onset of puberty and of GtH synthesis and release was studied by chronic administration of testosterone (T) and/or an analog of gonadotropin-releasing hormone (G). Sustained administration of T+G increased the mRNA levels of the PLH subunit to the values characteristic of sexually mature fish, and also increased the plasma levels of LH. However, these changes did not result in the acceleration of sexual maturation. The mRNA levels of the bFSH subunit were slightly stimulated, but remained about 1/10 of the values characteristic of sexually mature fish. It is concluded that the stimulation of FSH gene expression and release does not lead to the acceleration of sexual maturity, and that the failure to sufficiently stimulate the bFSH subunit gene expression may underlie the inability of the treatments to advance sexual maturity. Consequently, FSH is suggested to be the key hormone to the initiation and completion of puberty in striped bass. Future efforts to induce precocious puberty in striped bass should focus on understanding the regulation of FSH synthesis and release and on developing technologies to induce these processes. Definite formulation of hormonal manipulation to advance puberty in the striped bass and the black carp seems to be premature at this stage. However, the project has already yielded a great number of experimental tools of DNA technology, slow-release systems and endocrine information on the process of puberty. These systems and certain protocols have been already utilized successfully to advance maturation in other fish (e.g. grey mullet) and will form a base for further study on fish puberty.
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Applebaum, Shalom W., Lawrence I. Gilbert, and Daniel Segal. Biochemical and Molecular Analysis of Juvenile Hormone Synthesis and its Regulation in the Mediterranean Fruit Fly (Ceratitis capitata). United States Department of Agriculture, 1995. http://dx.doi.org/10.32747/1995.7570564.bard.
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Original Objectives and revisions: (1) "To determine the biosynthetic pathway of JHB3 in the adult C. capitata CA in order to establish parameters for the future choice and synthesis of suitable inhibitors". Modified: to determine the pattern of FR-7 biosynthesis during normal reproductive maturation, and identify enzymes potentially involved in its synthesis. (2) "To correlate allatal epoxidase activity to the biosynthesis of JHB3 at different stages of reproductive maturation/vitellogenesis and evaluate the hypothesis that a specific JH-epoxidase may be rate limiting". Modified: to study the effects of epoxidase inhibitors on the pattern of allatal JH biosynthesis in vitro and on female reproduction in vive. (3) "To probe and clone the gene homologous to ap from C. capitata, determine its exon-intron organization, sequence it and demonstrate its spatial and temporal expression in larvae, pupae and adults." The "Medfly" (Ceratitis capitata) is a serious polyphagous fruit pest, widely distributed in subtropical regions. Damage is caused by oviposition and subsequent development of larvae. JH's are dominant gonadotropic factors in insects. In the higher Diptera, to which the Medfly belongs, JHB3 is a major homolog. It comprises 95% of the total JH produced in vitro in D. melanogaster, with JH-III found as a minor component. The biosynthesis of both JH-III and JHB3 is dependent on epoxidation of double bonds in the JH molecule. The specificity of such epoxidases is unknown. The male accessory gland D. melanogaster produces a Sex Peptide, transferred to the female during copulation. SP reduces female receptivity while activating specific JH biosynthesis in vitro and inducing oviposition in vive. It also reduces pheromone production and activates CA of the moth Helicoverpa armigera. In a previous study, mutants of the apterous (ap) gene of D. melanogaster were analyzed. This gene induces previteilogenic arrest which can be rescued by external application of JH. Considerable progress has been made in recombinant DNA technology of the Medfly. When fully operative, it might be possible to effectively transfer D. melanogaster endocrine gene-lesions into the Medfly as a strategy for their genetic control. A marked heterogeneity in the pattern of JH homologs produced by Medfly CA was observed. Contrary to the anticipated biosynthesis of JHB;, significant amounts of an unknown JH-like compound, of unknown structure and provisionally termed FR-7, were produced, in addition to significant amounts of JH-III and JHB3. Inhibitors of monooxygenases, devised for their effects on ecdysteroid biosynthesis, affect Medfly JH biosynthesis but do not reduce egg deposition. FR-7 was isolated from incubation media of Medfly CA and examined by various MS procedures, but its structure is not yet resolved. MS analysis is being done in collaboration with Professor R.R.W. Rickards of the Australian National University in Canberra, Australia. A homologue of the ap gene of D. melanogaster exists in the Medfly. LIM domains and the homeo-domain, important for the function of the D. melanogaster ap gene, are conserved here too. Attempts to clone the complete gene were unsuccessful. Due to the complexity of JH homologs, presence of related FR-7 in the biosynthetic products of Medfly CA and lack of reduction in eggs deposited in the presence of monooxygenase inhibitors, inhibition of epoxidases is not a feasible alternative to control Medfly reproduction, and raises questions which cannot be resolved within the current dogma of hormonal control of reproduction in Diptera. The Medfly ap gene has similar domains to the D. melanogaster ap gene. Although mutant ap genes are involved in JH deficiency, ap is a questionable candidate for an endocrine lesion, especially since the D. melanogoster gene functions is a transcription factor.
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Saillant, Eric, Jason Lemus, and James Franks. Culture of Lobotes surinamensis (Tripletail). Mississippi Department of Marine Resources, January 2014. http://dx.doi.org/10.18785/ose.001.
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The Tripletail, Lobotes surinamensis, is a pelagic fish found in tropical and sub-tropical waters of all oceans. Tripletails are often associated with floating debris and make frequent incursions in bays and estuaries where they are targeted by recreational fishermen. In Mississippi waters the species is typically present during the late spring and summer season that also correspond to the period of sexual maturation and spawning (Brown-Peterson and Franks 2001). Tripletail is appreciated as a gamefish but is also prized for its flesh of superior quality. The fast growth rate of juveniles in captivity documented by Franks et al. (2001) and the excellent quality of Tripletail flesh both contribute to the potential of this species for marine aquaculture. In addition, the production of cultured juveniles would be precious to develop a better understanding of the biology, early life history and habitat use of Tripletail larvae and juveniles, a topic largely undocumented to date, through experimental releases and controlled studies. The culture of tripletail thus supports the Tidelands Trust Fund Program through improved conservation of natural resources, potential enhancement of fisheries productivity and potential development of a new economic activity on the Gulf coast producing tripletail via aquaculture. The Objective of this project was to initiate development of methods and techniques needed to spawn captive held tripletail broodfish and raise their offspring to evaluate their growth and development in captivity. In this report we will present the results of studies aiming to develop methods and protocols for captive spawning of tripletail and the first data obtained on the early development of tripletail larvae. A major issue that was encountered with tripletail broodstock development during the project lied in the difficulties associated with identifying the sex of adults caught in the wild and candidates for being incorporated in mating sets for spawning. This issue was addressed during the course of the project by examining the potential of a non-lethal method of hormonal sexing. The results of these preliminary investigations are presented in the third part of this report. All protocols used in the project were determined with the guidance of the Institutional Animal Care and Use Committee (IACUC) of the University of Southern Mississippi (USM IACUC protocol number 10100108).
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Funkenstein, Bruria, and Cunming Duan. GH-IGF Axis in Sparus aurata: Possible Applications to Genetic Selection. United States Department of Agriculture, November 2000. http://dx.doi.org/10.32747/2000.7580665.bard.
Full textAbstract:
Many factors affect growth rate in fish: environmental, nutritional, genetics and endogenous (physiological) factors. Endogenous control of growth is very complex and many hormone systems are involved. Nevertheless, it is well accepted that growth hormone (GH) plays a major role in stimulating somatic growth. Although it is now clear that most, if not all, components of the GH-IGF axis exist in fish, we are still far from understanding how fish grow. In our project we used as the experimental system a marine fish, the gilthead sea bream (Sparus aurata), which inhabits lagoons along the Mediterranean and Atlantic coasts of Europe, and represents one of the most important fish species used in the mariculture industry in the Mediterranean region, including Israel. Production of Sparus is rapidly growing, however, in order for this production to stay competitive, the farming of this fish species has to intensify and become more efficient. One drawback, still, in Sparus extensive culture is that it grows relatively slow. In addition, it is now clear that growth and reproduction are physiological interrelated processes that affect each other. In particular sexual maturation (puberty) is known to be closely related to growth rate in fish as it is in mammals, indicating interactions between the somatotropic and gonadotropic axes. The goal of our project was to try to identify the rate-limiting components(s) in Sparus aurata GH-IGF system which might explain its slow growth by studying the ontogeny of growth-related genes: GH, GH receptor, IGF-I, IGF-II, IGF receptor, IGF-binding proteins (IGFBPs) and Pit-1 during early stages of development of Sparus aurata larvae from slow and fast growing lines. Our project was a continuation of a previous BARD project and could be divided into five major parts: i) obtaining additional tools to those obtained in the previous project that are necessary to carry out the developmental study; ii) the developmental expression of growth-related genes and their cellular localization; iii) tissue-specific expression and effect of GH on expression of growth-related genes; iv) possible relationship between GH gene structure, growth rate and genetic selection; v) the possible role of the IGF system in gonadal development. The major findings of our research can be summarized as follows: 1) The cDNAs (complete or partial) coding for Sparus IGFBP-2, GH receptor and Pit-1 were cloned. Sequence comparison reveals that the primary structure of IGFBP-2 protein is 43-49% identical to that of zebrafish and other vertebrates. Intensive efforts resulted in cloning a fragment of 138 nucleotides, coding for 46 amino acids in the proximal end of the intracellular domain of GH receptor. This is the first fish GH receptor cDNA that had been cloned to date. The cloned fragment will enable us to complete the GH - receptor cloning. 2) IGF-I, IGF-II, IGFBP-2, and IGF receptor transcripts were detected by RT-PCR method throughout development in unfertilized eggs, embryos, and larvae suggesting that these mRNAs are products of both the maternal and the embryonic genomes. Preliminary RT-PCR analysis suggest that GH receptor transcript is present in post-hatching larvae already on day 1. 3) IGF-1R transcripts were detected in all tissues tested by RT-PCR with highest levels in gill cartilage, skin, kidney, heart, pyloric caeca, and brain. Northern blot analysis detected IGF receptor only in gonads, brain and gill cartilage but not in muscle; GH increased slightly brain and gill cartilage IGF-1R mRNA levels. 4) IGFBP-2 transcript were detected only in liver and gonads, when analyzed by Northern blots; RT-PCR analysis revealed expression in all tissues studied, with the highest levels found in liver, skin, gonad and pyloric caeca. 5) Expression of IGF-I, IGF-II, IGF-1R and IGFBP-2 was analyzed during gonadal development. High levels of IGF-I and IGFBP-2 expression were found in bisexual young gonads, which decreased during gonadal development. Regardless of maturational stage, IGF-II levels were higher than those of IGF-L 6) The GH gene was cloned and its structure was characterized. It contains minisatellites of tandem repeats in the first and third introns that result in high level of genetic polymorphism. 7) Analysis of the presence of IGF-I and two types of IGF receptor by immunohistochemistry revealed tissue- and stage-specific expression during larval development. Immunohistochemistry also showed that IGF-I and its receptors are present in both testicular and ovarian cells. Although at this stage we are not able to pinpoint which is the rate-limiting step causing the slow growth of Sparus aurata, our project (together with the previous BARD) yielded a great number of experimental tools both DNA probes and antibodies that will enable further studies on the factors regulating growth in Sparus aurata. Our expression studies and cellular localization shed new light on the tissue and developmental expression of growth-related genes in fish.
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Grumet, Rebecca, Rafael Perl-Treves, and Jack Staub. Ethylene Mediated Regulation of Cucumis Reproduction - from Sex Expression to Fruit Set. United States Department of Agriculture, February 2010. http://dx.doi.org/10.32747/2010.7696533.bard.
Full textAbstract:
Reproductive development is a critical determinant of agricultural yield. For species with unisexual flowers, floral secualdifferentation adds additional complexity, that can influenec productivity. The hormone ethylene has long, been known to play a primary role in sex determination in the Cucumis species cucumber (C. sativus) and melon (C. melo). Our objectives were to: (1) Determine critical sites of ethylene production and perception for sex determination; (2) Identify additional ethylene related genes associated with sex expression; and (3) Examine the role of environment ami prior fruit set on sex expression, pistillate flower maturation, and fruit set. We made progress in each of these areas. (1) Transgenic melon produced with the Arabidopsis dominant negative ethylene perception mutant gene, etrl-1, under the control of floral primordia targeted promoters [AP3 (petal and stamen) and CRC (carpel and nectary)], showed that ethylene perception by the stamen primordia, rather than carpel primordia, is critical for carpel development at the time of sex determination. Transgenic melons also were produced with the ethylene production enzyme gene. ACS, encoding l-aminocyclopropane-lcarboylate synthase, fused to the AP3 or CRC promoters. Consistent with the etr1-1 results, CRC::ACS did not increase femaleness; however, AP3::ACS reduced or eliminated male flower production. The effects of AP3:ACS were stronger than those of 35S::ACS plants, demonstratin g the importance of targeted expression, while avoiding disadvantages of constitutive ethylene production. (2) Linkage analysis coupled with SNP discovery was per formed on ethylene and floral development genes in cucumber populations segregating for the three major sex genes. A break-through towards cloning the cucumber M gene occurred when the melon andromonoecious gene (a), an ACS gene, was cloned in 2008. Both cucumber M and melon a suppress stamen development in pistillate flowers. We hypothesized that cucumber M could be orthologous to melon a, and found that mutations in CsACS2 co-segregated perfectly with the M gene. We also sought to identify miRNA molecules associated with sex determination. miRNA159, whose target in Arabidopsis is GAMYB[a transcription factor gene mediating response to10 gibberellin (GA)], was more highly expressed in young female buds than male. Since GA promotes maleness in cucumber, a micro RNA that counteracts GAMYB could promote femaleness. miRNA157, which in other plants targets transcription factors involved in flower development , was expressed in young male buds and mature flower anthers. (3) Gene expression profiling showed that ethylene-, senescence-, stress- and ubiquitin-related genes were up-regulated in senescing and inhibited fruits, while those undergoing successful fruit set up-regulated photosynthesis, respiration and metabolic genes. Melon plants can change sex expression in response to environmental conditions, leading to changes in yield potential. Unique melon lines with varying sex expression were developed and evaluated in the field in Hancock, Wisconsin . Environmental changes during the growing season influenced sex expression in highly inbred melon lines. Collectively these results are of significance for understanding regulation of sex expression. The fact that both cucumber sex loci identified so far (F and M) encode isoforms of the same ethylene synthesis enzyme, underscores the importance of ethylene as the main sex determining hormone in cucumber. The targeting studies give insight into developmental switch points and suggest a means to develop lines with earlier carpel-bearing flower production and fruit set. These results are of significance for understanding regulation of sex expression to facilitate shorter growing seasons and earlier time to market. Field results provide information for development of management strategies for commercial production of melon cultivars with different sex expression characteristics during fruit production.
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Perl-Treves, Rafael, Rebecca Grumet, Nurit Katzir, and Jack E. Staub. Ethylene Mediated Regulation of Sex Expression in Cucumis. United States Department of Agriculture, January 2005. http://dx.doi.org/10.32747/2005.7586536.bard.
Full textAbstract:
Monoecious species such as melon and cucumber develop separate male and female (or bisexual) flowers on the same plant individual. They display complex genetic and hormonal regulation of sex patterns along the plant. Ethylene is known to play an important role in promoting femaleness and inhibiting male development, but many questions regarding critical sites of ethylene production versus perception, the relationship between ethylene and the sex determining loci, and the possible differences between melon and cucumber in this respect are still open. The general goal of the project was to elucidate the role of ethylene in determining flower sex in Cucumis species, melon and cucumber. The specific Objectives were: 1. Clone and characterize expression patterns of cucumber genes involved in ethylene biosynthesis and perception. 2. Genetic mapping of cloned genes and markers with respect to sex loci in melon and cucumber. 3. Produce and analyze transgenic melons altered in ethylene production or perception. In the course of the project, some modifications/adjustments were made: under Objective 2 (genetic mapping) a set of new mapping populations had to be developed, to allow better detection of polymorphism. Under Objective 3, cucumber transformation systems became available to us and we included this second model species in our plan. The main findings of our study support the pivotal role of ethylene in cucumber and melon sex determination and later stages of reproductive development. Modifying ethylene production resulted in profound alteration of sex patterns in melon: femaleness increased, and also flower maturation and fruit set were enhanced, resulting in earlier, more concentrated fruit yield in the field. Such effect was previously unknown and could have agronomic value. Our results also demonstrate the great importance of ethylene sensitivity in sex expression. Ethylene perception genes are expressed in sex-related patterns, e.g., gynoecious lines express higher levels of receptor-transcripts, and copper treatments that activate the receptor can increase femaleness. Transgenic cucumbers with increased expression of an ethylene receptor showed enhanced femaleness. Melons that expressed a defective receptor produced fewer hermaphrodite flowers and were insensitive to exogenous ethylene. When the expression of defective receptor was restricted to specific floral whorls, we saw that pistils were not inhibited by the blocked perception at the fourth whorl. Such unexpected findings suggest an indirect effect of ethylene on the affected whorl; it also points at interesting differences between melon and cucumber regarding the mode of action of ethylene. Such effects will require further study. Finally, our project also generated and tested a set of novel genetic tools for finer identification of sex determining genes in the two species and for efficient breeding for these characters. Populations that will allow easier linkage analysis of candidate genes with each sex locus were developed. Moreover, effects of modifier genes on the major femaleness trait were resolved. QTL analysis of femaleness and related developmental traits was conducted, and a comprehensive set of Near Isogenic Lines that differ in specific QTLs were prepared and made available for the private and public research. Marker assisted selection (MAS) of femaleness and fruit yield components was directly compared with phenotypic selection in field trials, and the relative efficiency of MAS was demonstrated. Such level of genetic resolution and such advanced tools were not used before to study these traits, that act as primary yield components to determine economic yields of cucurbits. In addition, this project resulted in the establishment of workable transformation procedures in our laboratories and these can be further utilized to study the function of sex-related genes in detail.