Inhibition by estradiol of human chorionic gonadotropin-induced progesterone accumulation in isolated human luteal cells: lack of mediation by prostaglandin F.

Estradiol has been previously reported to be a potent inhibitor of hCG-stimulated progesterone accumulation in isolated cells from human corpora lutea of the menstrual cycle. We assessed the role of prostaglandin (PG) in this in vitro estradiol-induced inhibition by measuring PGF and adding a blocker of PG synthesis (indomethacin) to the incubation medium. The inhibition by estradiol of hCG-stimulated progesterone accumulation occurred without any increase in PGF accumulation in the incubations. Furthermore, PGF accumulation was markedly reduced (P less than 0.05) at all concentrations of indomethacin testes (0.1, 1, and 10 microgram/ml), but the inhibitory effect of estradiol on hCG-stimulated progesterone accumulation was not prevented. These data suggest that the inhibitory effect of estradiol observed in vitro is not mediated by PGs.