Monooxygenase enzyme activity in alcoholics with varying degrees of liver damage

Monooxygenase enzymes are involved in the biotransformation of drugs and of environmental carcinogens. The activity of 7-ethoxycoumarin 0-deethylase and associated NADPH-cytochrome c reductase was determined in 9000 g supernatant from bioptically obtained liver specimens from patients with various liver diseases in order to study in vitro drug metabolising capacity. Monooxygenase and reductase activity was significantly higher in the livers of 21 patients with alcoholic liver disease (fatty liver, alcoholic hepatitis, cirrhosis of the liver) than in 22 normal controls or in six patients with chronic active hepatitis. The raised activity of drug-metabolising enzymes obtained from alcoholics with liver damage differs from normal values found in five alcoholics without liver disease. Both groups were comparable in respect to the amount of alcohol consumed and duration of abuse. A strikingly low monooxygenase activity was observed in eight patients with cirrhosis of the liver and ascites, with, however, no apparent effect on reductase activity. The results show that alcoholic liver disease is associated with enhanced monooxygenase and reductase activity, but alcoholism, per se, is not. This rise of drug-metabolising enzyme activity could lead to selectively increased rates of biotransformation in patients with alcoholic liver damage.