INCREASED ALCOHOL-DEHYDROGENASE INDEPENDENT ETHANOL OXIDATION AT HIGH ETHANOL CONCENTRATIONS IN ISOLATED RAT HEPATOCYTES - THE EFFECT OF CHRONIC ETHANOL FEEDING

  • 1 January 1981
    • journal article
    • research article
    • Vol. 217  (1) , 133-137
Abstract
Rates of ethanol oxidation in isolated rat hepatocytes increased with increasing ethanol concentrations even at near-saturation of the alcohol dehydrogenase (ADH) pathway. After inhibition of ADH by pyrazole, approximately 30% of ethanol-oxidizing activity remained and this activity of the non-ADH pathway was also dependent upon ethanol concentration. The apparent Km of the non-ADH pathway for ethanol was 13 mM, which is comparable to the value for the microsomal ethanol oxidizing system. Inhibition of catalase by azide affected the activity of the non-ADH pathway by less than 10%. After chronic ethanol feeding, the rates of ethanol oxidation in isolated hepatocytes and liver slices increased significantly compared to those in pair-fed controls. This adaptive increase of ethanol oxidation was more striking at a high ethanol level (30 mM) than at a low one (10 mM). Significant differences between the 2 groups remained even after inhibition of ADH and catalase. The results suggest that the microsomal ethanol oxidizing system may account for the major part of the non-ADH pathway.