Differing effects of chronic ethanol consumption by mice on liver microsomal metabolism of xenobiotics: 1-nitropyrene, nicotine, aniline, and N-nitrosopyrrolidine.

The effect of ethanol consumption by male CF-1 mice on liver microsomal enzyme activities has been investigated. The total microsomal cytochrome P-450 content was increased by 38%, while cytochrome b5 was decreased by 31%, which are characteristic alterations in liver microsomes following ethanol consumption. Other alterations included a decreased NADPH cytochrome c reductase activity and increased NADPH-supported rates of N-nitrosopyrrolidine and aniline hydroxylation. While ethanol consumption did not alter the total metabolism of nicotine, the rates of N- and C-hydroxylation were differently affected. The 5'-hydroxylation of nicotine was increased by 83%, while the N'-oxidation was decreased by 31%. Changes in the microsomal metabolism of the environmental carcinogen 1-nitropyrene included a slight reduction in the overall metabolism, which can be accounted for by a reduction in the formation of one phenolic metabolite, 1-nitropyren-3-ol.