Effect of chronic ethanol feeding on glutathione and glutathione-related enzyme activities in rat liver.

The effects of chronic ethanol consumption on liver glutathione concentrations and glutathione-related enzyme activities were studied in rats over a period of 1-9 weeks. The animals received a liquid diet containing 36% of calories as ethanol or isocaloric carbohydrate. Glutathione concentrations were significantly enhanced following ethanol intake with increases of 99% after 3 weeks and a progressive decrease thereafter. Glutathione S-transferase activity reached a maximum increase of 36% after 2 weeks of ethanol feeding. Glutathione peroxidase activity remained unchanged for the first 6 weeks of treatment, with a tendency to decrease in the last weeks of ethanol consumption. Our findings indicate that chronic ethanol administration profoundly modifies the hepatic metabolism of glutathione and may thus have important effects on the detoxification of xenobiotics by the liver.