Abstract

• Cytochrome P-450 is a terminal oxidase of the hepatic microsomal monooxygenase system associated with the oxidative biotransformation of a varity of lipophilic endogenous and exogenous compounds, and generally is assayed by CO-binding spectro-photometry of dithionite-reduced samples. In well fed normal male rats with or without stress condition, the dffect of antiulcer drug; cimetidine, sulpiride and diazepam on the level of microsomal cytochrome P-450 were determined. Only stress condition produced on significant effect in cytochrome P-450 contents. Administration of cimetidine, sulpiride and diazepam in this condition caused a 44.1%~87.5% increment in cytochrome P-450, diazepam produced the most increase. After diazepam treatment of rats, the peak position of cytochrome P-450 shifted to a longer wave length of 452 nm.