[Foreign substance-degrading enzyme system of the human liver. Modification by alcohol, other exogenous factors and liver diseases].

Ethanol was found to be capable to stimulate the microsomal xenobiotic-metabolizing enzyme system of human liver. However, this effect was seen only in cases of alcoholic liver damage (fatty liver, alcoholic hepatitis). Alcoholics without alcoholic liver injury had enzyme activities comparable to control patients, who had no liver disease. On ethanol abstinence the enzyme stimulation was reversible within 20 days. Stimulation of xenobiotic-metabolizing enzyme activity in alcoholic liver disease seems to be related to ethanol induced toxicity. The highest enzyme activities were observed in patients on enzyme inducing drugs (2- to 6 fold increase), whereas in alcoholic liver disease enzyme activities were doubled. These results suggest that the stimulation of the microsomal enzyme system caused by ethanol is different from the enzyme induction seen on inducing drugs.