Prolactin modulation of dehydroepiandrosterone sulfate secretion

To clarify the controversy about the effect of prolactin (PRL) on dehydroepiandrosterone sulfate (DHEA-S), this study was undertaken to investigate the effects of alterations in plasma PRL on plasma DHEA-S concentrations in hyperprolactinemic women, as well as in normal male subjects. DHEA-S was measured in a group of 21 women with hyperprolactinemia, galactorrhea, and amenorrhea (PRL: 257 ± 89 ng/ml; mean ± SEM). In these women, mean plasma concentrations of DHEA-S (2.54 ± 0.2 μg/ml) were significantly higher (p < 0.005) than those in 41 normal control women (1.78 ± 0.1 μg/ml) and those in a group of 11 amenorrheic patients (1.77 ± 0.2 μg/ml). Eight women with hyperprolactinemia were given 5 mg of bromocriptine each day for 4 consecutive weeks. Within 1 week of medication, PRL levels fell by 60% (p < 0.05). To test whether lowering normal plasma levels of PRL would affect plasma concentrations of DHEA-S, five normal male subjects received a 48-hour infusion of dopamine at an average rate of 6 μg/kg/min. Plasma levels of PRL fell by 60% (p < 0.01) after 8 hours of infusion, and DHEA-S decreased by 27% by 16 hours (p < 0.05). These data suggest that PRL modulates the secretion of DHEA-S: an increase in plasma levels of PRL is correlated with elevated concentrations of DHEA-S, whereas a decrease in PRL is followed by a fall in DHEA-S.