Effects of prolactin on steroid production by human luteal cells in vitro

The effects of prolactin on steroidogenesis were studied in dispersed luteal cells prepared from human corpora lutea of the menstrual cycle. Prolactin, at concentrations of 0.1-1000 ng/ml, had no effect on progesterone production by luteal cells during short-term incubation (3 h). However, in two out of five corpora lutea, higher concentrations of prolactin (100 and 1000 ng/ml) significantly reduced the oestradiol-17 beta production induced by human chorionic gonadotrophin (hCG; 10 i.u./ml); lower doses of prolactin had little effect. In the remaining corpora lutea, prolactin failed to affect either basal or hCG-induced production of oestradiol-17 beta. These results are discussed in relation to the mechanism by which prolactin influences human ovarian function.