Modification of hepatic drug metabolizing enzyme activities and their induction by dietary protein
General Pharmacology 11(5): 443-450
The hepatic drug metabolizing enzyme activities were measured after feeding various protein diets to rats. No changes were found in the hepatic cytochrome P-450 content and ethoxycoumarin O-deethylase activity but aryl hydrocarbon hydroxylase activity was decreased by a low protein diet. Epoxide hydrase and UDP glucuronosyltransferase activities were enhanced by the low protein diet. No significant changes of drug metabolizing enzyme activities were found when rats were fed 64% protein diet in comparison with 27% protein diet. Phenobarbitone was a potent inducer of cytochrome P-450, epoxide hydrase and activated UDP-glucuronosyltransferase even during dietary protein deficiency. Methylcholanthrene induced aryl hydrocarbon hydroxylase and native UDPglucuronosyltransferase activities. Both inducers cause some induction of ethoxycoumarin O-deethylase activity even during protein deficiency.