Activity of Alcohol Dehydrogenase and Acetaldehyde Dehydrogenases in the Liver and Placenta during the Development of the Rat

Abstract

The ontogenetic development of the enzymes alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenases (ALDH I and II) was followed in rats. ADH could be detected just before birth and increased gradually to reach 82% of adult values at 47 days. ALDH I and II were present from day 15 of gestation, increased rapidly at birth, and reached 80—90% adult values at 47 days. The ratio between ALDH and ADH activities decreased gradually during ontogenesis. The relative subcellular distribution of all enzymes was identical before birth, 7 days after birth and in adults. The placental activities of ADH and ALDH I and II were studied at 15 and 20 days of pregnancy. ADH could not be detected in placentas. Low activities of ALDH I and II were present in placentas studied at 15 days of gestation, and still lower activities were found in placenta at 20 days.

Disposition of Ethanol and Acetaldehyde in Late Pregnant Rats and Their Fetuses

“…In addition, although fetal liver alcohol dehydrogenase is absent at day 17 of pregnancy, in the 2 1-day pregnant rat, fetal alcohol dehydrogenase is very low, and when observed values are used to calculate liver capacity for ethanol oxidation, it appears to be approximately 0.12 pmol/min/fetal liver, which represents 20% of adult liver activity. This ethanol oxidation capacity is in agreement with other reports in rats and in humans (27)(28)(29)(30), and it is very low compared to the initial net input of ethanol from mother to fetus, estimated at approximately 8 Fmol/min (from data in Table 2). Thus, maximal fetal liver capacity is less than 2% of the total ethanol received by the fetus.…”

“…Lower maternal acetaldehyde levels that reach fetal tissues or the placenta seem to be metabolized by these structures. At late gestation, both placenta and fetal liver have been found to contain aldehyde dehydrogenase activity (27,29,(33)(34)(35), and the activities found in the present study correspond to 25% and 1.5% of adult levels in fetal liver and placenta, respectively (Table 6).…”

“…This is a consequence of the rapid passage of ethanol through membrane structures and the fact that no alcohol dehydrogenase activity is present in the rat placenta (27). This explains the rapid equilibration in the maternal and fetal compartments after maternal ethanol administration.…”

Development of Alcohol Dehydrogenase and Aldehyde Dehydrogenases in the Offspring of Female Rats Chronically Treated with Ethanol

“…No significant differences in the development of hepatic protein content, ADH activity and ALDH activities were found between the two groups (table 1). The values corresponded well with findings in foetuses and pups of the same Wistar strain fed ordinary pellets (Sjoblom et a/. 1978).…”

“…Previous investigations have shown that the activities of ADH and ALDH are low in the prenatal life of the rat (Raiha et a/. 1967;Rawat 1976;Sjoblom et a/. 1978).…”