Oestradiol Exerts Disparate Effects on Ultrastructure and Steroidogenesis of Ovarian Theca from Preovulatory Hamster Follicles(Endocrinology)

概要

論文の詳細を見る
Oestrogens can induce atresia in vivo in mammals; and can diminish oestradiol-17β(OEJ secretion from granulosa cells in vitro though apparently not at the level of aromatase. We therefore investigated whether OE_2 exerts the latter effect by inhibiting oestrogen precursor (androgen) synthesis at the level of the theca. Thecal shells were explanted from ovarian follicles of hamsters and were cultured in medium alone (control) or in medium plus either OE_2(1μg/ml) or OE_2 (1μg/ml) plus the OE_2-antagonist, CI-628 (1×10^<-4>M). OE_2 induced a 48% increase in lipid droplet number and a 46% decrease in mitochondrial number as compared to control. Although ultrastructural modifications were observed, OE_2 did not alter progesterone (P_4) or androstenedione (A_4) secretion; unexpectedly, CI-628 enhanced both. The OE_2-induced increase in lipid droplet number in thecal shells is correlated with atresia/luteinization. Although mitochondrial number was reduced, the effect may not be physiologically relevant since thecal P_4 secretion was unchanged. The lack of effect on smooth endoplasmic reticulum correlated with the unchanged thecal A_4 secretion, I.e., substrate for aromatization was unaltered. We therefore believe that the atretogenic effects of OE_2 that we and others have observed with respect to hamster ovarian follicles in vitro and in vivo, are not exerted at the level of thecal A_4 production.
社団法人日本動物学会の論文
1991-08-15