Role of hepatic acetaldehyde dehydrogenase in alcoholism: demonstration of persistent reduction of cytosolic activity in abstaining patients.

In alcoholic patients with fatty liver the activity of cytosolic, but not of mitochondrial, acetaldehyde dehydrogenase was lower than in controls. Sequential studies in abstaining alcoholics showed that the cytosolic acetaldehyde dehydrogenase activity remained low, although the previously low activity of alcohol dehydrogenase returned to normal values. It is suggested that reduced cytosolic acetaldehyde dehydrogenase activity may represent a primary defect in alcoholism and is, in part, the cause of the abnormal acetaldehyde metabolism in alcoholic patients. Isoelectric focusing showed distinct isoenzymes of acetaldehyde dehydrogenase in the liver cytosolic and mitochondrial fractions. A survey of eight control subjects and twenty alcoholic patients showed no evidence of a missing or abnormal enzyme in the alcoholic group.