Stimulation by human chorionic gonadotrophin of oestradiol production by dispersed cells from human corpus luteum: comparison with progesterone production; utilization of exogenous testosterone.

Cell suspensions were prepared from tissue samples of human corpora lutea obtained during the mid- and late-luteal phase of the menstrual cycle. Both oestradiol and progesterone production by dispersed cells were stimulated by similar concentrations of human chorionic gonadotrophin (hCG). As the degree of stimulation of production by hCG was greater for progesterone than for oestradiol (five- to tenfold compared two- to threefold higher than basal production), the ratio of progesterone to oestradiol produced varied according to the level of trophic stimulation. A comparison of cell suspensions prepared form mid- to late-luteal phase corpora lutea, exposed to the same concentration of hCG (10 i.u./ml) in vitro, did not reveal a shift to oestradiol production in the late-luteal phase. Provision of additional testosterone during incubation raised the level of oestradiol production by dispersed luteal cells. At an optimum concentration of testosterone (l mumol/l), oestradiol synthesis was not raised further in the presence of hCG or N6, O2'-dibutyryl cyclic AMP, suggesting a lack of induction or activation of the aromatase system by gonadotrophin in short-term cultures. Basal and stimulated levels of progesterone production were not significantly impaired in the presence of testosterone.