Alcohol-metabolizing enzymes in placenta and fetal liver: effect of chronic ethanol intake.

Alcohol dehydrogenase and different subcellular distribution of aldehyde dehydrogenase (ALDH) in fetal liver and placenta at 15 and 21 days of gestation were studied in three different groups of pregnant rats: alcoholic, pair-fed, and rat solid chow diet animals. Chronic ethanol intake during pregnancy produced a decrease in fetal body and liver weight but an increase of placenta weight. No alcohol dehydrogenase was detected in placenta at any stage of gestation, nor in fetal liver at 15 days although a low activity was found at 21 days. No significant difference was observed from fetuses of alcoholic and nonalcoholic mothers. Subcellular aldehyde dehydrogenase distribution in placenta was similar to that in adult liver. Although no cytosolic ALDH was detected in fetal liver at any period of gestation, low activities were found in placenta and fetal liver at 15 days of pregnancy in other subcellular fractions. However, at 21 days the placental activity decreased while that of fetal liver increased markedly. The increase of the fetal liver ALDH was especially noticeable in the mitochondrial fraction in which the activity was approximately 10-fold higher than in the placenta mitochondrial fraction. A small decrease in placenta and fetal liver ALDH was observed in alcoholic rats. The role of the placenta ALDH in the acetaldehyde placental transfer is discussed.