ETHANOL EXPOSURE DURING THE LAST WEEK OF GESTATION IN THE RAT - INHIBITION OF THE PRENATAL TESTOSTERONE SURGE IN MALES WITHOUT LONG-TERM ALTERATIONS IN SEX BEHAVIOR
Rf. Mcgivern et al., ETHANOL EXPOSURE DURING THE LAST WEEK OF GESTATION IN THE RAT - INHIBITION OF THE PRENATAL TESTOSTERONE SURGE IN MALES WITHOUT LONG-TERM ALTERATIONS IN SEX BEHAVIOR, Neurotoxicology and teratology, 20(4), 1998, pp. 483-490
In utero ethanol exposure decreases the prenatal testosterone (T) surg
e in male rats. To determine the functional significance of this suppr
ession. we measured sex behavior in adult litter representatives of pr
egnant rats that were administered a fortified liquid diet containing
35% ethanol-derived calories from day 15 of gestation through parturit
ion. Control dams were pair-fed an isocaloric liquid diet with the eth
anol calories replaced by sucrose. Results from the behavioral studies
showed that gonadally intact fetal alcohol-exposed (FAE) males exhibi
ted little masculine sex behavior in the first of four weekly sessions
. However, their behavior in the subsequent three tests was indistingu
ishable from pair-led controls. Lordosis quotients in the same males f
ollowing castration and estrogen and progesterone treatment were under
10%. In castrated FAE females, no effects of prenatal ethanol exposur
e were observed in masculine behaviors following androgen replacement
or feminine sex behaviors following estrogen and progesterone replacem
ent. Additional studies measured the duration of prenatal ethanol expo
sure necessary to inhibit the prenatal T surge in order to determine w
hether the inhibition was due to a direct effect of the drug. Results
revealed an inhibition of the surge in males exposed to ethanol from d
ays 14 through 20 of pregnancy. days 14 through 16 of pregnancy, or da
ys 17 through 20 of pregnancy. A normal surge of T was observed on day
s 18-19 of gestation in cont;ol fetuses. These findings indicate that
ethanol does not have to be present in blood at the time of the surge
to have an inhibitory effect. They also reveal that the surge can be i
nhibited with as little as 2436 h of ethanol exposure prior to its nor
mal appearance on day 18 of gestation. In spite of this inhibition of
the prenatal T surge, the behavioral results indicate that normal masc
ulinization and defeminization of sex behavior occurs in FAE males exp
osed to ethanol after the beginning of the period of differentiation o
f the hypothalamus and testes. (C) 1998 Elsevier Science Inc.