Effect of acute ethanol ingestion on prolactin in menopausal women using estradiol replacement

Epidemiologic studies suggest that women who consume ethanol are at an increased risk for developing breast cancer. Two randomized, crossover studies were performed to examine the effects of ethanol on prolactin in menopausal women using transdermal estradiol. In study 1, transdermal estradiol patches (0.15 mg) were administered to menopausal women (n = 7) the day before ethanol administration. At 8.00 h, the women ingested ethanol (1 ml/kg, 95% ethanol) or an isocaloric carbohydrate drink. Prolactin levels were measured frequently for 6.3 h. Serum ethanol levels reached a broad peak from 40 to 100 min after initiation of ethanol ingestion. Serum prolactin levels were significantly higher after ethanol ingestion than after the isocaloric carbohydrate drink ingestion (p < 0.03). Study 2 was identical to study 1 except that the transdermal estradiol patches were removed after completion of ethanol or carbohydrate ingestion. In study 2, serum prolactin was greater after ethanol ingestion than after carbohydrate ingestion (p < 0.001). In menopausal women using transdermal estradiol, acute ethanol ingestion is associated with an increase in serum prolactin.