The inhibition of androstenedione production in mature thecal cells from the ovary of the domestic hen (Gallus domesticus): evidence for the involvement of progestins.
In the 24 hours before ovulation, there is an abrupt decline in the ability of theca cells from the largest chicken preovulatory follicle to produce androstenedione from all substrates except dehydroepiandrosterone. In this study, we tested the hypothesis that progesterone from granulosa cells might inhibit andostenedione production by the adjacent theca cells. Physiological concentrations of progesterone inhibited andostenedione production by dispersed thecal cells from the substrate 17 alpha-hydroxyprogesterone but not dehydroepiandrosterone in both a dose- and time-dependent manner. In contrast, the metabolites of progesterone, 17 alpha-hydroxyprogesterone, and androstenedione at a high concentration (100 nM) failed to produce such an inhibitory effect. In addition, this inhibitory effect of progesterone was reversed by the protein synthesis inhibitor cycloheximide. The results of this study seem to suggest that progesterone acts indirectly through its nuclear receptor to induce the synthesis of a protein that possibly inhibits C17,20 lyase activity and/or C17,20 lyase gene expression.
Woolveridge
I
I
Department of Physiology and Pharmacology, University of Southampton, UK.
Peddie
M J
MJ
D000735:Androstenedione / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D000818:Animals; D002478:Cells, Cultured; D002645:Chickens; D005260:Female; D006801:Humans; D010053:Ovary / Q000166:cytology*; D011372:Progestins / Q000502:physiology*; D013254:Steroid 17-alpha-Hydroxylase / Q000037:antagonists & inhibitors; D013799:Theca Cells / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology
D011372:Progestins; D000735:Androstenedione; D013254:Steroid 17-alpha-Hydroxylase