The dose-response relationship in brain. plasma, and adrenal mon()aminc changes after acute oral ethanol administration (I, 2. 4 g./kg body wt) was sl u-licd in virgin rats lo determine whether the response lo the highest dose differed in 21-day pregnant ani11ials. and to assess the potential consequences of ethanol on the neurotransmitlcr systems of their fctusc s. Blood ethanol and acetaldchyde concentrations in blood increased progrcs:;ivcly with the ctha1wl dose in virgin rats, and values in pregnant animals were very similar. Ethan,>! concentration in fetal blood and amniotic Ouid did not differ from that in mother's blood whereas fetal acctaldchydc concentrations were negligible. In a dose-related manner, ethanol decreased brain DA. DOPAC and 5HT ..:cncentrations did not affect those of NA and 5HIAA, or adrenal A and NA concentrations, whereas it enhanced plasma NA levels. Basal levels of monoamincs and their changes after ethanol intake did not differ in pregnant and virgin rats. Monoaminc and metabolite concentrations were much lower in fetal tlian in maternal brains whereas plasma and adrenal catecholamine concentrations were very similar and naternal ethanol intake did not modify these fetal parameters in the fetus. Results are in agreement wi1 h the known similar metabolic response to ethanol in fed pregnant and virgin rats. The lack of fetal monoamine response to maternal ethanol intake may be a consequence of the incapacity of fetal liver to form acetaldchydc and the ability of the placenta to oxidize maternal acctaldehyde which protects the fetus fr,m1 maternal alcohol intake at late gestation.