[Stimulation of pituitary gonadotropin secretion after castration in rainbow trout: variation of the response during the reproductive cycle].
Bilateral castration of male rainbow Trout resulted in increased levels of circulating gonadotropin, as measured by radioimmunoassay, but the response varied depending on the season. In early May the increase was 12 ng/ml after 30 days, when compared to the intact control but later in the month at the time when a peak of gonadotropin level is observed in normal fish, the increase was 25 ng/ml after 13 days. At the beginning of August, when spermatogenesis commences, the increase was 9 ng/ml after 12 days. In September, when spermatogenesis is ending, an increase of 20 ng/ml was found after 7 days, but only 50% of the animals responded. In December, during spermiation, an increase of 90 ng/ml was found after 7 days.
D000818:Animals; D002369:Castration; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D012487:Salmonidae / Q000502:physiology*; D012621:Seasons; D013091:Spermatogenesis; D013737:Testis / Q000502:physiology*; D014337:Trout / Q000502:physiology*
D007987:Gonadotropin-Releasing Hormone
Stimulation de la secrétion gonadotrope hypophysaire après castration chez la Truite arc-en-ciel; variation de la réponse au cours du cycle reproducteur