Angiotensin II modulates steroidogenesis in granulosa and theca in the rabbit ovary: its possible involvement in atresia.
Accumulating evidence has shown the ovary of mammals to contain an intrinsic renin-angiotensin system that has been ascribed an autocrine-paracrine role. The present study in the female rabbit ovary investigated the putative in vitro action of angiotensin II (A II) on basal and gonadotropin-induced steroidogenesis. Ovarian follicles from immature female rabbits treated with pregnant mare's serum gonadotropin (PMSG) were dissected out and a complete separation of the theca interna from the granulosa layer was performed, to demonstrate that A II affects separately the two individual cellular components of the follicular wall. We could show that theca is a source of estradiol whose production under human chorionic gonadotropin (hCG) stimulation was reduced by A II. At the same time, A II increased the in vitro hCG-stimulated secretion of testosterone by theca. In granulosa, A II decreased hCG-stimulated aromatization of androstenedione to estradiol but did not alter the release of hCG-stimulated progesterone production. These results suggest that A II could induce locally an increase in follicular fluid androgen/estrogen ratio and possibly participate in causing atresia.
Féral
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EP CNRS 009, Laboratoire de Biochimie, CHU Caen, France.
Le Gall
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Leymarie
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D000804:Angiotensin II / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D004958:Estradiol / Q000378:metabolism; D004967:Estrogens / Q000032:analysis / Q000378:metabolism; D005260:Female; D005496:Follicular Atresia / Q000378:metabolism*; D015571:Follicular Fluid / Q000737:chemistry; D006064:Gonadotropins, Equine / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D011374:Progesterone / Q000032:analysis / Q000378:metabolism; D011817:Rabbits; D013739:Testosterone / Q000378:metabolism; D013799:Theca Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
D006063:Chorionic Gonadotropin; D004967:Estrogens; D006064:Gonadotropins, Equine; D000804:Angiotensin II; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol