Cumene hydroperoxide supported oxidation of ethanol by microsomes from chronic ethanol treated rats: Differences from an NADPH supported system

Chronic alcohol consumption increases NADPH dependent microsomal oxidation of ethanol. The present studies investigated whether cumene hydroperoxide (CM) supported the oxidation of ethanol and hydroxyl radical (^.OH) scavengers by microsomes from alcohol-treated rats and to evaluate whether the increased oxidation found with NADPH also occurs with CM. CM supported alcohol oxidation by microsomes from alcohol-treated and control rats; however, rates were identical in both preparations. CM did not effectively support the oxidation of ^.OH scavengers by microsomes from either preparation, suggesting that ^.OH was not effectively generated. These results indicate that ethanol oxidation in the presence of CM reflects an ^.OH independent, cytochrome P450 mediated reaction. Perhaps the inability of CM to support induced rates of ethanol oxidation after chronic ethanol consumption may reflect the induction of a P450 isozyme which cannot function as an effective peroxygenase.