The effect of chronic alcohol ingestion on free radical defense in the miniature pig.

Cellular protection from free radical reactions was measured in hepatic tissue from controls and miniature pigs fed ethanol. The activities of copper-zinc superoxide dismutase (CuZnSOD) and glutathione peroxidase were lower and the activity of manganese superoxide dismutase (MnSOD) was higher in the pigs fed ethanol than in controls. Glutathione concentration was lower in the pigs fed ethanol than in controls. Ethanol consumption did not result in increased lipid peroxidation as assessed by thiobarbituric acid-reactive substances. The ethanol-induced effects on the activities of the superoxide dismutases may be a reflection of available metals and/or a response to increased hepatic concentration of oxygen radicals. Because the protection afforded by the glutathione system was altered, pigs fed ethanol may be at risk of peroxidative damage with continued ethanol exposure.