Abstract

• It is now well established that ethanol excerts different effect on hepatic cellular metabolism, depending mainly on the duration of its intake. And induction of quantitative and qualitative alterations in the cytochrome P-450 of hepatic microso-mes after chronic ethanol feeding is a well-documented phenomenon. But the effect of ethanol ingestion on the drug metabolism appear paradoxic and the ability of chronic ethanol ingestion to potentiate the carcinogenicity of 2-acetyl-aminofluorene(2-AAF) by microsomal activation is not confirmed yet. The present study was undertaken to demonstrate the effects of 15%, 30% ethanol and a commercial liquor feeding for 16 weeks on the lipid in the rat liver, hepatic microsomal cytochrome P-450 and b5, and to elucidate whether or not ethanol-induced rat microsomes can increase the risk of cancer by increasing the rate of metabolic activation of 2-AAF in vitro. The results are followings. 1) The chronic alcohol feeding increased the contents of total cholesterol and triglyceride in the liver, but did not make a significant influence on the phospholipid contents of liver. 2) The 8 week alcohol feeding increased the hepatic microsomal cytochrome P-450 without the changeof cytochrome b5 but the 16 week feeding decreased P-450 significantly. 3) The chronic alcohol feeding elevated the AAF N-hydroxylation continuously but did not influence on AAF ring-hydroxylation. 4) The correlation of AAF N-hydroxylation and the increases of hepatic lipid contents was indicated.