Effects of ethanol and acetaldehyde on myocardial ornithine decarboxylase activity

Abstract Intraperitoneal ethanol or acetaldehyde had no effect on myocardial ornithine decarboxylase activity in the rat. When given with propranolol there was a decrease in enzyme activity. In the isolated, perfused heart, high concentrations of acetaldehyde inhibited the enzyme activity, while ethanol had no effect. Ethanol or acetaldehyde had no direct effect on the cytosolic enzyme activity. It is suggested that ethanol or its metabolites both directly inhibit myocardial ornithine decarboxylase activity and indirectly stimulate it by catecholamine release. The inhibitory effect appears to be mediated through a diminished rate of synthesis of the enzyme.