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In this study, we have estimated the phenotypic and genetic relationships between prepuberal plasma FSH level (FSH and logFSH) of ewe lambs of the Lacaune meat breed and their reproductive performance at first mating (fertility and prolificacy). Hormonal levels were assayed in a single blood sample collected at approximately 5 weeks of age (mean ± S.D. =(More)
Cryptorchidism was induced in 5 pre-pubertal lambs and 7 adult rams, 5 months after surgery, testicular weight and membrane protein content were 4-fold lower than in the control. The total number of Leydig cells per testis was markedly decreased but their size was not changed. In contrast, the total number of Sertoli cells per testis was not affected but(More)
Total follicular populations and peripheral plasma concentrations of LH, FSH, prolactin, oestradiol-17 beta and progesterone during the preceding cycle were studied in two breeds of sheep (Romanov and Ile-de-France) which differed widely in their ovulation rates (3.2 and 1.5 respectively). No LH parameters could be correlated with the follicular details(More)
Cette étude a pour but de mesurer les teneurs en FSH et LH plasmatique des produits mâles et femelles et la croissance testiculaire des mâles issus de 16 pères Lacaune sélectionnés d'après leur index de prolificité en fermes (8 prolifiques H et 8 non prolifiques B) et de mères Romanov et FI Lacaune X Romanov. Elle porte sur 161 agneaux dont 100 mâles et 61(More)
Sertoli cells are involved in the control of spermatogenesis. In adult animals, the Sertoli cell stocks, fixed before puberty, are highly correlated with those of the germ cells. Some factors influencing Sertoli cell stock formation have been analyzed: 1) Early hemicastration of impuberal animals showed that the proliferative activities of the Sertoli and(More)
In sheep as in rat, it has been highly suggested that neuronal histamine (HA) participates to the estradiol (E2)-induced GnRH and LH surges, through H1 receptor. With the aim of determining if E2 could act directly on HA neurons, we examined here whether HA neurons express estrogen receptor alpha (ERα) in the ewe diencephalon during the breeding season. We(More)
Cette étude estime la variabilité phénotypique et génétique des variables FSH et log FSH mesurées à partir d'un seul prélèvement sanguin aux environs de 33 jours, sur 892 agnelles Lacaune viande nées de juillet à septembre 1983 dans 21 élevages et issues de 42 pères utilisés en insémination. Les effets « élevage » et « père » sont très significatifs.(More)
This paper reports the effects of X-irradiation on ovulation rate, cyclicity and progesterone and FSH levels in Ile-de-France ewes (4 control and 16 irradiated) after they were treated during the breeding season. The doses used (800 and 2 400 R) destroyed 50% of all size classes of the follicular population. Ovulation occurred in 87% of the treated ewes(More)
Plasma concentrations of LH, FSH, prolactin and testosterone, pituitary concentrations of gonadotrophins and prolactin, and hypothalamic LH-RH were measured in normal, sexually mature male rats at regular intervals from 1 to 30 days after castration or cryptorchidism. Bilateral castration resulted in a marked decrease in testosterone levels 24 h after(More)
The effects of anterior hypothalamic deafferentation on luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), and sexual behavior in the ovariectomized ewe was investigated. Response to injection of estradiol benzoate (50 mcg) was measured before and after surgery. In all 4 cases the estradiol-induced release of LH and PRL(More)
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