Gonadotrophin dependence of steroidogenesis by human corpora lutea of different ages during the menstrual cycle.

In vitro production of progesterone and estradiol by human corpora lutea of different ages was evaluated in the presence or absence of human chorionic gonadotrophin (HCG). Progesterone production by the luteal tissue was enhanced by as little as 0.1 IU/ml HCG and maximally stimulated by approximately 10 IU/ml HCG. Estradiol production was enhanced by 100 IU/ml HCG. Under control conditions, the synthetic activities of progesterone and estradiol were highest in the luteal tissue isolated from the mid-luteal phase corpora lutea and were lowest in the late luteal phase corpora lutea. The addition of HCG (100 IU/ml) stimulated progesterone and estradiol production by early and mid-luteal phase corpora lutea, whereas HCG had no effects on steroidogenesis by late luteal phase corpora lutea. The results suggest that the age of the corpus luteum might be an important factor governing luteal cell responsiveness to gonadotrophins.