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Registros recuperados: 79
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Apport des connaissances fondamentales au contrôle du cycle reproducteur des poissons d'étang : limites et perspectives [The control of the reproductive cycle in pond fish: limits and perspectives] Animal Physiology
Breton, B.; Fostier, A.; Jalabert, B.; Weil, C..
Les possibilités d'un contrôle de la reproduction des poissons sont basées sur une bonne connaissance de la gamétogenèse, de son contrôle endocrinien et de son déroulement au cours du cycle reproducteur annuel. On examinera le rôle clé joué par le complexe hypothalamo-hypophysaire qui intègre les facteurs de l'environnement et répond en élaborant et sécrétant une ou plusieurs hormones impliquées dans le développement des gonades. Ces dernières vont, grâce à la sécrétion de stéroïdes sexuels, solliciter d'autres organes comme le foie, et mobiliser des réserves corporelles pour les intégrer sous forme de vitellus dans les ovocytes. Les facteurs de l'environnement susceptibles d'intervenir dans la régulation du cycle sexuel sont nombreux : facteurs physiques...
Tipo: Book Chapter Palavras-chave: QP Physiology.
Ano: 1980 URL: http://phy043.tours.inra.fr:8080/archive/00000351/
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Cinétique de libération in vitro de 17 alpha hydroxy - 20 beta dihydroprogestérone par des follicules de Truite arc-en-ciel, Salmo gairdnerii Animal Physiology
Fostier, A.; Jalabert, B.; Campbell, C.; Terqui, M.; Breton, B..
Un dosage radioimmunologique spécifique a été utilisé pour suivre la libération de 17 alpha hydroxy - 20 beta dihydroprogestérone par des follicules ovariens entiers de 2 truites arc-en-ciel, au cours de la maturation ovocytaire, induite in vitro par la gonadotropine glycoproteique maturante de salmonidé (s-GtH). Sans stimulation gonadotrope, la production de ce progestagène reste très faible. Elle s'accroît fortement avec l'augmentation des niveaux de s-GtH maintenus dans le milieu. A chacun de ces niveaux, elle est plus importante pour des follicules provenant de la femelle donneuse la plus proche de sa date d'ovulation supposée. Par ailleurs les fortes quantités de progestagène produites sont en accord avec les fortes teneurs mesurées dans le plasma...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1981 URL: http://phy043.tours.inra.fr:8080/archive/00000376/
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Immunological cross-reaction between pituitary gonadotropin from North atlantic fish Animal Physiology
Bye, V.J.; Breton, B.; Billard, R..
Pituitary extracts of 14 species of fish from the North Atlantic were tested in rainbow trout and carp gonadotropin radioimmunoassays (RIA). The poor cross-reaction and low gonadotropin content measured in the pituitary extracts indicate that RIA used for trout and carp gonadotropins are unsuitable for these species. The degree of specificity in the two systems does not reflect the phylogenetic relationships of the tested species. It is suggested that fish gonadotropins are species specific so that a sensitive RIA must be developed for each family investigated. A species specificity between fish and mammalian gonadotropins was suggested by work on goldfish spermatogenesis (Billard et al., 1970; Billard and Escaffre, 1973). Specificity among some groups of...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1980 URL: http://phy043.tours.inra.fr:8080/archive/00000332/
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Ultrastructural studies on experimentally induced vitellogenesis in juvenile rainbow trout (Salmo Gairdbneri R.) Animal Physiology
Upadhyay, S.N.; Breton, B.; Billard, R..
Juvenile rainbow trout (weighing 10 or 20 g) were treated thrice weekly for 10 weeks with salmon-gonadotropin (S-GTH), salmon pituitary extract (S-PE), S-GTH plus estradiol-17beta, and estradiol-17beta alone. The effects of these treatments on the oocytes were studied at ultrastructural level. Saline-injected control fish contained oocytes at previtellogenic stage of development. S-GTH. (0.1 or 0.5 microg/g) induced a synthesis of endogenous yolk in the oocyte cytoplasm but failed to initiate incorporation of exogenous yolk or vitellogenin into the oocytes. S-GTH (0.1 microg/g) in combination with estradiol-17beta (1 microg/g) produced similar results to those with S-GTH alone. Estradiol-17beta alone failed to induce vitellogenesis. In contrast, S-PE (10...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1978 URL: http://phy043.tours.inra.fr:8080/archive/00000264/
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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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Caractérisation partielle d'un facteur hypothalamique de libération des hormones gonadotropes chez la carpe (Cyprinus carpio L.). Etude in vitro Animal Physiology
Breton, B.; Jalabert, B.; Weil, C.; Reinaud, P..
L'influence de différents facteurs sur la secrétion in vitro d'hormone gonadotrope par des hypophyses de Carpe a été étudiée grâce au choix d'un milieu d'incubation favorable. Après filtration sur Séphadex G 25 d'extraits acides réalisés, soit à partir d'hypothalamus, soit à partir de neurohypophyses, une activité de type "releasing factor" a été mise en évidence dans des fractions correspondant à un poids moléculaire inférieur à 5,000. Cette activité se distingue d'une part de celle de l'ocytocine et de la vasopressine et d'autre part de celle de neuroamines: adrénaline, noradrénaline, sérotonine et dopamine, qui ne montrent pas d'activité stimulante propre sur la secrétion gonadotrope in vitro. Par ailleurs, la secrétion de "releasing factor" in vitro...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1975 URL: http://phy043.tours.inra.fr:8080/archive/00000172/
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Rapid determination of the sex of puberal salmonid fish by a technique of immunoagglutination Animal Physiology
Le Bail, P.Y.; Breton, B..
The present study describes a rapid, simple and specific method to determine the sex of salmonid fish. This method is based on the detection by immunoagglutination of the serum vitellogenin of females in which oocytes are undergoing vitellogenesis. The application of this technique demonstrated the possibility of detecting vitellogenin in female brown trout as early as April and in all female Atlantic salmon captured in Brittany during the fishing season, between March and June.
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1981 URL: http://phy043.tours.inra.fr:8080/archive/00000380/
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Mise en évidence d'une régulation non stéroidïenne d'origine testiculaire sur la sécrétion d'hormone gonadotrope (GtH) chez la truite arc-en-ciel Animal Physiology
Breton, B.; Billard, R..
L'augmentation de la sécrétion gonadotrope (GtH) après castration chez la Truite arc-en-ciel est partiellement inhibée par du liquide séminal traité au charbon. Un extrait protéique testiculaire est inactif. Ce résultat laisse supposer l'existence dans le liquide séminal d'un facteur inhibiteur de la sécrétion gonadotrope. [The postcastration increase of gonadotropin secretion in the rainbow trout, was partially inhibited by charcoal treated seminal liquid. Protein testicular extract did not have any effect. This result demonstrates the probable existence of an inhibitory factor of gonadotropin secretion in the seminal plasma of the Trout.]
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1980 URL: http://phy043.tours.inra.fr:8080/archive/00000324/
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Pituitary and plasma gonadotrophin levels and spermatogenesis in the goldfish Carassius auratus after methallibure treatment Animal Physiology
Breton, B.; Jalabert, B.; Billard, R..
The level of gonadotrophin measured by radioimmunoassay in fully mature male goldfish was about 15 ng carp gonadotrophic hormone (c-HG)/ ml plasma and 30 microg c-HG/g pituitary (wet weight). After treatment for 35 days with methallibure (added to the water at the rate of 2 p.p.m./day), the level of gonadotrophin in the blood was very low and remained at the pretreatment level in the pituitary. This suggested that releasing factor might control either synthesis or discharge of gonadotrophin from the pituitary. These results have also shown that type B spermatogonia and meiosis were gonadotrophin dependent but that the development of spermatocytes into spermatids did not require high concentrations of gonadotrophin. Spermiation was suppressed when the...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1973 URL: http://phy043.tours.inra.fr:8080/archive/00000127/
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Pituitary response to LH-RH at different stages of gametogenesis in the rainbow trout (Salmo gairdneri) Animal Physiology
Weil, C.; Billard, R.; Breton, B.; Jalabert, B.; Reinaud, P..
Pituitary response to LH-RH has been studied in the male and female rainbow trout (Salmo gairdneri) at different stages of gametogenesis. The male was hardly sensitive at the onset of spermatogenesis, but a response occured at the spermatid stage and continued during spermatogenesis and spermiation. We particularly studied the end of the female cycle. Response was low in immature fishes and in the early stages of oocyte maturation, but became stronger at vitelline maturation. The relationships of these responses to plasma and pituitary t-GTH levels are discussed. [La sensibilité hypophysaire au LH-RH a été étudiée chez la truite Arc-en-ciel mâle et femelle à différents stades de la gamétogenèse. Chez le mâle, elle est presque nulle au début de la...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1978 URL: http://phy043.tours.inra.fr:8080/archive/00000265/
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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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Dosage radioimmunologique des gonadotropines plasmatiques chez Carassius auratus, au cours du nycthémère et pendant l'ovulation [Gonadotropin radioimmunologic assay in Carassius auratus for a 24-hr period during ovulation] Animal Physiology
Breton, B.; Billard, R.; Jalabert, B.; Kann, G..
L'évolution du taux de gonadotropines a été suivie dans le plasma par dosage radioimmunologique chez Carassius auratus au cours du nycthémère et pendant la période d'ovulation. Les résultats mettent en évidence : 1) L'existence d'une forte décharge hormonale dans le sang au moment de l'ovulation (Fig. 5). 2) Une évolution cyclique du contenu hormonal plasmatique au cours du nycthémère particulièrement nette chez les femelles (Fig. 3), avec un maximum à 11 heures du matin dans le nycthémère de juillet. [Changes in plasmatic gonadotropin level were observed by radioimmunologic assay in Carassius auratus for a 24-hr period during ovulation. The following results were found: 1) A high hormone discharge into the blood at the time of ovulation (Fig. 5). 2). A...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1972 URL: http://phy043.tours.inra.fr:8080/archive/00000123/
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Plasma estradiol-17beta and gonadotropin during ovulation in rainbow trout (Salmo gairdneri R.) Animal Physiology
Fostier, A.; Weil, C.; Terqui, M.; Breton, B.; Jalabert, B.; Reinaud, P..
A radioimmunoassay (RIA) for estradiol-17beta (E2-17beta) with a chromatographic step has been tested on rainbow trout plasma. Overloading and dilution tests gave satisfactory results. Intracardiac injection of E2-17beta (10 microg/kg) in July gave a peak in the first 30 min after injection ; return to the basic level occurred within the next 24 hrs. Using RIA, trout-gonadotropin (t-GTH) and E2-17beta were followed in trout plasma during the very last stages of the reproductive cycle. Oocyte maturity was determined simultaneously. t-GTH increase during maturation and ovulation was confirmed while E2-17beta dropped before oocyte maturation to reach a low level when t-GTH was high. [Un dosage radioimmunologique de l'oestradiol-17beta comprenant une étape de...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1978 URL: http://phy043.tours.inra.fr:8080/archive/00000251/
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Evolution des niveaux plasmatiques de la gonadotropine glycoprotéique et de la 17 alpha hydroxy-20 beta dihydroprogesterone au cours de la maturation et de l'ovulation chez la truite arc-en-ciel, Salmo gairdnerii Animal Physiology
Fostier, A.; Breton, B.; Jalabert, B.; Marcuzzi, O..
L'évolution des concentrations plasmatiques en hormone gonadotrope glycoprotéique (GTH) et en 17alpha hydroxy-20beta dihydroprogestérone a été suivie au cours de l'ovulation chez 6 truites arc-en-ciel, à l’aide de dosages radio-immunologiques de prélèvements effectués tous les 2 jours. II apparaît un premier accroissement progressif et modéré des niveaux de la GTH avant et pendant l'ovulation (10 à 20 ng/ml), accompagné d'une rapide et forte montée des niveaux de la 17 alpha 20 beta OHP (plusieurs centaines de nanogrammes par millilitre). Les concentrations du progestagène reviennent à celles précédant la montée ovulatoire en une vingtaine de jours, alors que l'on assiste à un nouvel accroissement, plus important, des niveaux de GTH (25 à 30 ng/ml). [The...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1981 URL: http://phy043.tours.inra.fr:8080/archive/00000375/
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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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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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Stimulation hypophysaire de la sécrétion oestradiol-17beta chez la carpe commune, Cyprinus carpio L. [Hypophysial stimulation of oestradiol-17beta secretion in carp, Cyprinus carpio L.] Animal Physiology
Fostier, A.; Breton, B.; Jalabert, B..
[Using radioimmunoassays, plasma levels of carp gonadotropin (c-GTH) and oestradiol-17beta (E2) are measured every day in Carp, during induced spawning (water temperature = 15 °C). Ten Carps injected twice intraperitonealy with a total extract of Carp hypophysis (0,6 mg/kg BW at J0 and 5,4 mg/kg BW at J1) are compared to a lot receiving only saline solution. No evolution is detected in that last group when in the experimental one E2 level increases with exogenous c-GTH (see table). Even if E2 levels are low at the end of vitellogenesis, steroidogenic structures remain sensitive to an exogenous hypophysial stimulation. Secretion ability differs within individuals (correlation coefficient between total estimated c-GTH and E2 = 0,15).]
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1979 URL: http://phy043.tours.inra.fr:8080/archive/00000290/
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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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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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Temperature and reproduction in tench: effect of a rise in the annual temperature regime on gonadotropin level, gametogenesis and spawning. I. The male Animal Physiology
Breton, B.; Horoszewicz, L.; Billard, R.; Bieniarz, K..
During a 9-month period (corresponding to a sexual cycle), the adult male tench, Tinca tinca, was kept in fish farm ponds receiving heated water from a power plant. In 1974, the males were submitted to three different temperature regimes : group I : ambiant temperature ; group II : ambiant temperature + 3°C ; group III : ambiant temperature + 6°C. The experiment was repeated in 1975, but only using groups I and III. The reproductive cycle and thermal treatment were studied from a quantitative analysis of spermatogenesis, the duration of the spawning cycle and radioimmunoassay (RIA) measurement of gonadotropin (GTH) in plasma and pituitary, using a carp RIA system turned out to be sensitive enough to assay tench GTH, which was expressed in a c-GTH...
Tipo: Journal (Paginated) Palavras-chave: QP Physiology.
Ano: 1980 URL: http://phy043.tours.inra.fr:8080/archive/00000328/
Registros recuperados: 79
Primeira ... 1234 ... Última
 

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