Metabolism of drugs by subfractions of hepatic microsomes from prolonged ethanol-treated rats

The effects of variation in dietary protein and ethanol on hepatic microsomal drug metabolism in the rat

The effect of chronic ethanol consumption and variations in dietary protein content on microsomal drug metabolism were studied in rats pair-fed liquid diets containing 10, 20, ro 30% dietary protein with or without ethanol. In vitro drug metabolism was measured by aminopyrine breath tests and aminopyrine blood elimination kinetics. In vitro drug metabolism was assessed by measuring aminopyrine N-demethylase activity in the hepatic microsomal fraction. The rate of elimination of aminopyrine in vivo was increased in all ethanol-fed animals (p less than 0.05) regardless of the protein content of the diet. Animals receiving 10 or 20% protein diets with ethanol showed a 36% increase in drug elimination over pair-fed controls as compared to a 17% increase in drug elimination over controls in animals receiving 30% protein diets. Microsomal aminopyrine N-demethylase activities were similar in ethanol/fed animals and pair-fed controls. Cytochrome P-450 content was increased in all ethanol-fed animals (p less than 0.05) but the increase was not dependent on dietary protein content. These results indicate that the effect of chronic ethanol feeding in enhancing drug metabolism in vivo is influenced by the dietary protein content.

Increased carbon tetrachloride hepatotoxicity after low-level ethanol consumption

Male rats provided with a 5 or 15% (v/v) ethanol solution as the sole source of fluid consumed ethanol at a rate of 11.4 or 24.9% of total calories (4.2 or 8.3 g/kg daily). After ethanol consumption lasting 1, 2 and 3 weeks the hepatotoxicity of CCl4 (0.1 ml/kg i.p.) was elevated by determination of serum activities of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase ( GPT), sorbitol dehydrogenase (SDH) and histological investigations. Carbon tetrachloride (CCl4)-induced liver damage was significantly greater in rats provided with ethanol than in the tap-water consuming controls. This potentiation of CCl4 hepatotoxicicty was fully developed already after a 1-week exposition to ethanol and was greater in the 15% than in the 5% ethanol group. Ethanol alone did not influence serum enzyme activities but increased microsomal aniline hydroxylation. There was, however, no clear-cut parallelism between potentiation of CCl4 hepatotoxicity and activation of aniline hydroxylation.