PRENATAL ETHANOL EXPOSURE INDUCES A SEXUALLY DIMORPHIC EFFECT ON DAILY WATER-CONSUMPTION IN PREPUBERTAL AND ADULT RATS

Previous studies have shown that female rats consume significantly mor e water than males on a weight basis, Because exposure to alcohol duri ng the last week of gestation is associated with incomplete behavioral defeminization in male rats, we examined daily water intake in fetal alcohol-exposed (FAE) males and females. Time-pregnant multiparous Spr ague-Dawley dams were administered an ethanol liquid diet containing 3 5% ethanol-derived calories from day 14 through parturition, At 80 day s of age, daily water consumption of FAE males and female litter repre sentatives was measured for 7 days. FAE males, but not females, consum ed significantly more water than their pair-fed counterparts. Subseque nt experiments determined that the increased water consumption in FAE males is present prepubertally, persists into mature adulthood, and is not influenced by prenatal or postnatal castration. Chronic estrogen treatment induced large increases in water consumption, but consumptio n of FAE males remained elevated over elevated pair-fed male consumpti on, indicating that pituitary sensitivity to estrogen was not increase d in FAE males. Morphometric studies of hypothalamic nuclei containing vasopressin cells revealed no long-term effects of prenatal ethanol e xposure on the volume of the supraoptic nucleus or paraventricular nuc leus in males, nor was an effect observed in the ventromedial nucleus measured as a control. In FAE females, the volume of the paraventricul ar nucleus was significantly smaller than chow-fed controls. Whereas b aseline plasma and pituitary arginine vasopressin (AVP) levels of FAE animals and pair-fed controls were not significantly different, AVP co ntent was significantly reduced in the septal/bed nucleus region in br ains of FAE animals of both sexes. Overall, these data indicate that p renatal ethanol exposure increases male water consumption in the absen ce of alterations in basal plasma AVP.