Rf. Mcgivern et al., PRENATAL ETHANOL EXPOSURE INDUCES A SEXUALLY DIMORPHIC EFFECT ON DAILY WATER-CONSUMPTION IN PREPUBERTAL AND ADULT RATS, Alcoholism, clinical and experimental research, 22(4), 1998, pp. 868-875
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.