Activity of alcohol dehydrogenase and aldehyde dehydrogenase in maternal liver, fetal liver and placenta of the near-term pregnant ewe.
The activity of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) was determined in the near-term pregnant ewe. There was little ADH activity in fetal liver (4.4%) and placenta (0.2%) compared with maternal liver. Low KM (microM acetaldehyde) ALDH activity was similar in the three tissues. High KM (mM acetaldehyde) ALDH activity was less in fetal liver (57%) and placenta (16%) compared with maternal liver. These data and the pharmacokinetics of ethanol and its proximate metabolite, acetaldehyde, in the near-term pregnant ewe indicate that ethanol elimination from the maternal-fetal unit is regulated primarily by maternal hepatic ADH-catalyzed biotransformation of ethanol, and low KM ALDH activity in the fetal liver and placenta protects the fetus from exposure to ethanol-derived acetaldehyde, which is produced primarily in the maternal compartment.
Clarke
D W
DW
Department of Pharmacology and Toxicology, Faculty of Medicine, Queen's University, Kingston, Ont.
Smith
G N
GN
Patrick
J
J
Richardson
B
B
Brien
J F
JF
D000079:Acetaldehyde / Q000097:blood / Q000493:pharmacokinetics; D000426:Alcohol Dehydrogenase / Q000378:metabolism*; D000444:Aldehyde Dehydrogenase / Q000378:metabolism*; D000818:Animals; D000431:Ethanol / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics; D005260:Female; D005333:Fetus / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008431:Maternal-Fetal Exchange; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D012756:Sheep
D000431:Ethanol; D000426:Alcohol Dehydrogenase; D000444:Aldehyde Dehydrogenase; D000079:Acetaldehyde