Stable prolactin level after enhanced estradiol production following dehydroepiandrosterone sulfate

To evaluate whether intravenous injection of dehydroepiandrosterone sulfate (DHEAS), by enhancing estradiol (E2) production, would stimulate prolactin (PRL) secretion in late pregnancy, maternal serum PRL was determined before and 1 to 5 hours after administration of 100 mg of DHEAS in a total of 41 women with normal or complicated late pregnancies (twin pregnancy, pre-eclampsia, intrahepatic cholestasis of pregnancy, diabetes). The basal serum PRL concentration in patients with diabetes was significantly lower than normal. The mean PRL level did not change significantly in any group in spite of the increase in serum E2 levels after the DHEAS injection. The lack of PRL response to a rapid rise in E2 may be due to the maximal inhibition of the PRL-inhibiting factor in the hypothalamus and/or maximal activation of the pituitary lactotrophs occasioned by the high estrogen environment during late pregnancy.