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Registros recuperados: 79
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Androgen and estrogen treatments alter steady state messengers RNA (mRNA) levels of testicular steroidogenic enzymes in the rainbow trout, Oncorhynchus mykiss Animal Physiology
Baron, D.; Fostier, A.; Breton, B.; Guiguen, Y..
Recent investigations have shown that estrogens have profound inhibitory effects on steroidogenic enzyme gene expressions before and after testicular differentiation in the rainbow trout, Oncorhynchus mykiss. This present study bring new data on juvenile rainbow trout treated with estrogens and androgens. Following a 8 days oral treatment of juvenile male with 17-ethynyl-estradiol (EE2, 20 mg/kg diet) or 11-hydroxyandrostenedione (11OH4, 10 mg/kg diet), we observed a fast and marked decrease of steady-state mRNA levels for 3HSD, P450scc, P450c17, and P450c11 enzymes in the testis. After completion of these treatments, mRNA levels of these enzymes remained low in EE2 treated males whereas in 11OH4 treated males they recovered their initial levels in 8 days....
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 2005 URL: http://phy043.tours.inra.fr:8080/archive/00000087/
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The annual reproduction cycle in adult carp in Poland: ovarian state and serum gonadotropin level Animal Physiology
Bieniarz, K.; Epler, P.; Breton, B.; Thuy, L.N..
In environmental conditions in Poland, new vitellogenesis began in carp just after the spawning season. This phase was correlated with the maintenance of a high serum, gonadotropin level, which decreased and remained low when the temperature was also low ; oogenesis remained blocked at the stage attained before the drop in temperature and gonadotropin level. The rise of temperature in May increased GTH and ovarian responsiveness to hypophysation treatment. Although pituitary function seemed normal in some fish, there was no spawning even after hypophysation treatment. Resorbing oocytes were present during the whole year, and a minimum rate of GTH secretion would be necessary to prevent massive resorption. Animals were ready for a new reproduction cycle...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1978 URL: http://phy043.tours.inra.fr:8080/archive/00000243/
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Changes in blood gonadotropin level in mature female carp following hypophysial homogenate injections Animal Physiology
Bieniarz, K.; Epler, P.; Thuy, L.N.; Breton, B..
A hypophysial homogenate injection increased blood gonadotropin level in adult female carp and maintained it at that level for three days after injection. The blood gonadotropin level in adult female carp seems to be dependent on the physiological condition of the ovary expressed by the relation of old oocytes with a completed vitellogenesis process to the new ones, and the relation of the oocytes with the nucleus shifted to the periphery to those with a centrally placed nucleus.
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1980 URL: http://phy043.tours.inra.fr:8080/archive/00000315/
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Sensibilité à la température des différentes étapes de la reproduction chez la truite arc-en-ciel Animal Physiology
Billard, B.; Breton, B..
No abstract.
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1977 URL: http://phy043.tours.inra.fr:8080/archive/00000199/
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Rhythms of reproduction in teleost fish Animal Physiology
Billard, R.; Breton, B..
Reproduction is a cyclic phenomenon which occurs periodically in fish , sometimes once every two or three years but more usually, once or several times a year. But if rhythm is defined as a succession of reproductive cycles, rhythmicity can hardly be an innate characteristic, since this cyclic reproductive activity is usually considered to result from adaptation to a changing environment mediated through the endocrine system. Fish live in a large variety of biotopes leading to a great diversity of reproductive patterns . This paper describes some types of reproductive cycle and their associated hormonal changes. The reproductive cycle is divided into two parts , gametogenesis and spawning. Gametogenesis is the formation of highly specialised gametes...
Tipo: Book Chapter Palavras-chave: QP Physiology.
Ano: 1978 URL: http://phy043.tours.inra.fr:8080/archive/00000274/
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Sur quelques problèmes de physiologie du sperme chez les poissons téléostéens Animal Physiology
Billard, R.; Breton, B..
No abstract.
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1976 URL: http://phy043.tours.inra.fr:8080/archive/00000217/
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Le cycle reproducteur chez les poissons téléostéens [The reproductive cycle in teleost fish] Animal Physiology
Billard, R.; Breton, B..
No abstract.
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1981 URL: http://phy043.tours.inra.fr:8080/archive/00000386/
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Immunocytologie et histochimie des cellules gonadotropes et thyréotropes hypophysaires chez la Carpe Cyprinus carpio Animal Physiology
Billard, R.; Breton, B.; Dubois, M.P..
Des anticorps préparés, l'un à partir d'un facteur gonadotrope de Carpe, l'autre d'un matériel hypophysaire de Carpe riche en TSH, permettent de séparer en immunofluorescence un type unique de cellules gonadotropes et un deuxième type cellulaire présumé thyréotrope dans l'hypophyse de la Carpe. Un anticorps anti LH ovine révèle la même population cellulaire, mais la LH ovine n'inhibe pas la fluorescence de l'Ac. antigonadotrope de Carpe. Un anticorps anti TSH bovine, actif chez les ruminants et le Porc, est sans action sur les cellules thyréotropes de l'hypophyse de la Carpe.
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1971 URL: http://phy043.tours.inra.fr:8080/archive/00000159/
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Maintien et restauration de la spermatogénèse par un extrait acétonique hypophysaire de carpe chez le Cyprin (Carassius auratus) traité au méthallibure [Effect of a carp pituitary acetonic extract on spermatogenesis in the "methallibure" treated goldfish Carassius auratus] Animal Physiology
Billard, R.; Breton, B.; Escaffre, A.M..
Le méthallibure administré en bains à la dose de 2 p.p.m. entraîne chez le poisson rouge (Carassius auratus) une inhibition de la spermatogenèse qui intéresse toutes les cellules germinales à l'exception des spermatogonies A. Lorsque les mâles soumis à ce traitement reçoivent en même temps des injections de poudre hypophysaire brute de Carpe, la spermatogenèse est maintenue et même fortement stimulée. Après la suppression du traitement au méthallibure, la spermatogenèse se rétablit complètement en 20 jours, mais la restauration est plus importante si les animaux reçoivent des injections de poudre hypophysaire brute de Carpe. [Administration of methallibure in the water at 2 p.p.m. rates inhibited the spermatogenesis of the goldfish Carassius auratus at...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1971 URL: http://phy043.tours.inra.fr:8080/archive/00000120/
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Endocrine control of the teleost reproductive cycle and its relation to external factors: salmonid and cyprinid models Animal Physiology
Billard, R.; Breton, B.; Fostier, A.; Jalabert, B.; Weil, C..
Most of the fish living in the temperate zone exhibit an annual reproductive cycle. Reproduction, or more precisely hatching, occurs when food is available for the fry in the wild. Therefore, reproduction is closely related to environment. Endocrine control of the reproductive cycle, one of the links between environment and reproduction, is examined in this paper. Two main groups presenting different reproductive strategies are considered : 1) Salmonids spawning in autumn and winter ; the large amount of yolk and the duration of embryogenesis and vesicle resorption delay release of the fry so that spawning is not strictly environment-dependent. 2) Cyprinids usually laying small eggs in spring and summer ; these fish are more environment-dependent, at least...
Tipo: Book Chapter Palavras-chave: QP Physiology.
Ano: 1978 URL: http://phy043.tours.inra.fr:8080/archive/00000275/
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Inhibition de la spermatogenèse du guppy (poisson Cyprinodontidae) par le méthallibure [Inhibitory effect of ICI 33828 (methallibure) on spermatogenesis in the guppy (Poecilia reticulata)] Animal Physiology
Billard, R.; Breton, B.; Jalabert, B..
L'utilisation du méthallibure, en bain, aux doses de 1 à 2 p.p.m., entraîne une inhibition de la spermatogenèse du Guppy, qui est plus lente que celle obtenue après hypophysectomie chirurgicale ; après 30 jours de traitement l'inhibition de la spermatogenèse n'est pas totale. Le taux de mortalité reste élevé (20 p. 100 au 306 jour à la dose de 1 p.p.m.) mais il est dû en partie au solvant utilisé. [Administration of methallibure at 1 to 2 p.p.m. rates in water inhibited spermatogenesis in the Guppy. The gonadosomatic index decreased after day 10 of treatment (fig. I A). A regression of the various germinal cells was also recorded, but at day 30 of treatment, the inhibition of spermiogenesis was not total (fig. I B.H). In all cases the effects were slower...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1970 URL: http://phy043.tours.inra.fr:8080/archive/00000116/
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La production spermatogénétique chez la truite [Production of spermatozoa by the rainbow trout] Animal Physiology
Billard, R.; Breton, B.; Jalabert, B..
Une technique de mesure spectrophotométrique de la concentration en spermatozoïdes du sperme de truite a été mise en œuvre et un certain nombre de mesures pratiquées pendant la période de reproduction ont montré que : 1) la concentration varie entre 10 x 10exp9 et 25 x 10exp9 spermatozoïdes par ml au début de la fraie (fig. 2) et diminue ensuite ; 2) la concentration du sperme dans le canal déférent n'est pas constante et diminue dans le sens antéro-postérieur (fig. 4) ; 3) la quantité de spermatozoïdes par gramme de testicule est très élevée au début de la fraie et diminue ensuite (fig. 5) ; 4) quelle que soit la fréquence des prélèvements, la quantité de spermatozoïdes récoltés dans les conditions de la pratique piscicole reste toujours faible par...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1971 URL: http://phy043.tours.inra.fr:8080/archive/00000121/
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On the inhibitory effect of some steroids on spermatogenesis in adult rainbow trout (Salmo gairdneri) Animal Physiology
Billard, R.; Breton, B.; Richard, M..
To test the antifertility effect of various steroids, fish were fed a diet containing steroids at two stages of the reproductive cycle: during spermatogenesis (June to November, experiment A) and during spermiation (November to February, experiment B). The fish in experiment A were given testosterone (T), methyltestosterone (MT), estradiol-17beta (E2), hexestrol (H), progesterone (Pg), and FGA (Fluorogestone acetate) at doses of 0.05 and (or) 0.5 mg/kg of food. In experiment B, T, MT, and E2 were given at a dose of 0.5 mg/kg of food. The fish received a daily ration amounting to 1% of their body weight. In experiment A, inhibition of testicular growth was total with 0.5 mg MT and 0.5 mg E2 and partial with 0.5 mg T/kg of food. In these groups, there was no...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1981 URL: http://phy043.tours.inra.fr:8080/archive/00000367/
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Régénération de la spermatogenèse du Cyprin hypophysectomisé Carassius auratus L. par un facteur gonadotrope hautement purifié de Carpe Animal Physiology
Billard, R.; Burzawa-Gérard, E.; Breton, B..
Un facteur gonadotrope, purifié à partir d'une poudre hypophysaire de Carpe et d'activité spécifique élevée, se révèle capable de restaurer la spermatogenèse et de provoquer la spermiation chez un Poisson Téléostéen hypophysectomisé, Carassius auratus L.
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1970 URL: http://phy043.tours.inra.fr:8080/archive/00000158/
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Les cellules de sertoli des poissons téléostéens. I- Etude ultrastructurale [The Sertoli cells of teleost Fish I- Fine structure] Animal Physiology
Billard, R.; Jalabert, B.; Breton, B..
Dans le testicule d'un certain nombre de Poissons Téléostéens les cellules somatiques intra-lobulaires peuvent être considérées comme des cellules de Sertoli qui interviennent dans la contention et la nutrition des cellules germinales et dans leur phagocytose si elles dégénèrent. Les cellules de Sertoli assurent en outre, à la fin de la spermatogenèse, un rôle dans l'accumulation et l'excrétion de lipides qui participent vraisemblablement à la formation du liquide séminal. Malgré la présence passagère de réticulum agranulaire, cette étude morphologique ne permet pas de conclure définitivement au caractère stéroïdogène de ces cellules de Sertoli. [The seminiferous lobules of testes of 5 Teleost species, in 2 of which at least “lobules boundary cells” have...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1972 URL: http://phy043.tours.inra.fr:8080/archive/00000115/
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L'insémination artificielle de la truite (Salmo gairdneri Richardson). III- Définition de la nature et de la molarité du tampon à employer avec les dilueurs d'insémination et de conservation [Artificial insemination of trout (Salmo gairdneri Richardson). III- Definition of the nature and molarity of the buffer to use with insemination and conservation diluents] Animal Physiology
Billard, R.; Jalabert, B.; Breton, B..
Des expériences ont été conduites dans le but de définir la nature et la molarité du tampon à utiliser avec les deux dilueurs d'insémination et de conservation définis précédemment. Les effets des différents tampons ont été testés d'une part sur la stabilité du pH du dilueur après introduction de quantités croissantes de NaOH et HCl, de liquide cœlomique et d'ovules et d'autre part sur le pourcentage de fécondation établi sur de petits lots de 200 ovules. Les conclusions sont les suivantes : Le dilueur d'insémination (solution de NaCl à 250 mosm) peut être avantageusement tamponné avec un tampon carbonate-bicarbonate 0,02 M, pH de 9,2 à 9,5 Ce tampon se révèle plus stable après introduction de grande quantité d'ovules que les autres tampons testés...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1974 URL: http://phy043.tours.inra.fr:8080/archive/00000132/
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Stimulation of gonadotropin secretion after castration in rainbow trout Animal Physiology
Billard, R.; Richard, M.; Breton, B..
The effects of bilateral castration on plasma gonadotropin (t-GtH), as measured by radioimmunoassay, were investigated in male rainbow trout at several stages in the reproductive cycle: at the start of spermatogenesis at the end of May, after its completion in September, and before and after the beginning of spermiation in October and December. Castration resulted in increased level of circulating immunoreactive t-GtH but the response varied with the season. The rise after castration was four times the initial value in May and September, and increased twofold in October and sevenfold in December. The duration of the response following castration was 4 months in May, 2 months in September, and less than 1 month in October and December.
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1977 URL: http://phy043.tours.inra.fr:8080/archive/00000187/
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Stimulation de la sécrétion gonadotrope hypophysaire après castration chez la truite arc-en-ciel; variation de la réponse au cours du cycle reproducteur Animal Physiology
Billard, R.; Richard, M.; Breton, B..
Chez la Truite arc-en-ciel ayant subi une castration bilatérale, le niveau de la gonadotropine circulante mesurée par radioimmunologie augmente, mais le type de réponse varie selon la période de l'année à laquelle l'opération est pratiquée. En mai, avant l'apparition du pic de sécrétion observé dans les conditions naturelles, l'augmentation des teneurs en gonadotropine après castration est lente et faible (8 ng/ml de plus que les témoins intacts après 30 jours). Elle est beaucoup plus rapide lorsque la castration est pratiquée fin mai, lors de l'apparition de ce pic (différence de 12 ng/ml après 13 jours). Ensuite, les différences par rapport aux témoins sont de 9 ng/ml après 12 jours en août (démarrage de la spermatogenèse), 10 ng/ml après 7 jours...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1976 URL: http://phy043.tours.inra.fr:8080/archive/00000204/
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Changes in plasma gonadotropin after ovariectomy and estradiol supplementation at different stages at the end of the reproductive cycle in the rainbow trout (Salmo gairdneri R.) Animal Physiology
Bommelaer, M.C.; Billard, R.; Breton, B..
To determine the effect of gonadal feedback on plasma GTH level, female rainbow trout were ovariectomized at three stages at the end of the reproductive cycle : at the end of vitellogenesis, during germinal vesicle migration and during the post-ovulatory period. A group of controls and one of castrates in each experiment were given an injection of physiological salt solution, and a third group of castrates was supplemented with estradiol- 17beta (E2) twice a week (200 µg/kg) from the day of surgery. The blood was sampled twice a week, and the GTH measured by RIA. At the end of vitellogenesis, castration induced a significant rise in the gonadotropic hormone level (P < 0.001 from post-surgical day 5), and that response, unimpeded by E2, was homogeneous...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1981 URL: http://phy043.tours.inra.fr:8080/archive/00000370/
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A study of salmon (Oncorhynchus tschawytscha) pituitary gonadotropin dissociation Animal Physiology
Breton, B..
Urea (8 M) treatment of salmon gonadotropin results in the dissociation of the hormone into two subunits. These subunits were separated using DEAE-cellulose chromatography and gel filtration on Ultrogel ACA 54, and studied for their molecular weights, electrophoretic, biological, and immunological properties. Molecular weights of the alpha and beta subunits were, respectively, 12,500 and 17,000 as determined by gel filtration and sodium dodecyl sulfate-gel electrophoresis. In anionic polyacrylamide gel electrophoresis, 7.5%, the alpha subunit, migrated more rapidly (Rf = 0.67) than the native hormone s-GtH (Rf = 0.38), and the beta subunit did not migrate. The biological activities of the alpha and beta subunits were less than 10% of the GtH. Reassociation...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1981 URL: http://phy043.tours.inra.fr:8080/archive/00000371/
Registros recuperados: 79
Primeira ... 1234 ... Última
 

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