Suppression of follicular cAMP and steroid response to gonadotrophins by pretreatment with gonadotrophin.
This study examines the effect of preincubation of sheep ovarian follicles with hCG or FSH on the ability of isolated theca and granulosa to increase cAMP levels in response to a second incubation with hCG or FSH. Secondly, the effect of preincubation of small follicles with hCG on androstenedione and testosterone production is examined in intact follicles. Preincubation with hCG resulted in a decrease in the ability of theca from large (4--6 mm in diameter) and small (1--3 mm) follicles and granulosa from large follicles to increase cAMP levels in response to a second exposure to hCG. Similarly, preincubation with FSH suppressed the response of isolated granulosa from small and large follicles to a second exposure to FSH. A partial, but significant inhibition of the response to the other hormone was observed after preincubation with both FSH and hCG. Intact small follicles pretreated with hCG were unable to increase testosterone secretion in response to a second exposure to hCG.
D000735:Androstenedione / Q000096:biosynthesis; D000818:Animals; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism*; D012756:Sheep; D013739:Testosterone / Q000096:biosynthesis
D006063:Chorionic Gonadotropin; D013739:Testosterone; D000735:Androstenedione; D005640:Follicle Stimulating Hormone; D000242:Cyclic AMP