The effect of serum prolactin levels on ovarian steroidogenesis

In order to assess the effect of hyperprolactinemia on ovarian steroidogenetic potential, a group of anovulatory hyperprolactinemic patients and a control group of anovulatory normoprolactinemic women were submitted to exogenous gonadotropin (hMG) stimulation under identical experimental conditions. Serum 17 beta-estradiol (E2) concentrations were determined before and after hMG stimulation. The mean basal serum E2 levels in the hyperprolactinemic group (22.7 +/- 3.3 pg/mL, mean +/- 1 SE) were significantly lower than in the normoprolactinemic control group (48.7 +/- 8.4 pg/mL, P less than .01). A significant negative correlation (r = -.6157, P less than .01) between basal serum E2 levels and basal serum prolactin (hPRL) concentrations was found. Following hMG stimulation, the serum E2 increment (delta E2) from basal E2 levels in the control group (491 +/- 91 pg/mL) was significantly higher than the increment in the hyperprolactinemic group (182 +/- 48 pg/mL, P less than .01), and a significant negative correlation was observed between basal serum hPRL levels and the logarithm of delta E2 (r = -.4744, P less than .05). Our results suggest that chronic hyperprolactinemia induces ovarian refractoriness to exogenous gonadotropin stimulation and substantially reduces its steroidogenetic potential.