Effect of stress by repeated immobilization on hepatic alcohol dehydrogenase activity and ethanol metabolism

Abstract

The hepatic activity of alcohol dehydrogenase was increased after 7, 14 and 42 days of stress induced by immobilization of rats for 2.5 hr day . A single immobilization had no effect on the activity of alcohol dehydrogenase. Immobilization for 14 days resulted in increases in the rates of ethanol metabolism. This was not associated with changes in the activity of the microsomal ethanol-oxidizing system, microsomal catalase, cytochrome P-450, or NADPH cytochrome c reductase. A decrease in the hepatic phosphorylation potential ([ATP]/[ADP][P i]) was found to be due to a decrease in [ATP] and an increase in [P i]; however, there were no changes in O 2 consumption by liver slices or in hepatic (Na + + K +)-stimulated adenosine triphosphatase activity. The increased rate of ethanol metabolism after stress remains unexplained since alcohol dehydrogenase activity is not rate-limiting in ethanol oxidation and there were no increases in ethanol oxidation by microsomes or in mitochondrial oxidative rate.