Effect of the hypolipidemic drug bezafibrate on the hepatic mixed function oxidase system of the rat: heterogeneity monooxygenase responses

Administration of 100 mg/Kg of the hypolipidemic drug Bezafibrate for five consecutive days to the rat causes a marked liver enlargement and an alteration of the mixed function oxidase (MFO) system. Cytochrome P-450 levels are increased in liver microsomes from treated rats by 80%, NADPH-cytochrome c reductase activity by 45% and aminopyrine N-demethylase activity by 40%. On the contrary, other MFO activities (p-nitroanisole O-demethylase, hexobarbital oxidase, aniline hydroxylase and zoxazolamine hydroxylase) remain unchanged. The type of P-450 hemoprotein induced shows different spectroscopic properties in the binding of CO, Type II and Type RI ligands in respect to cytochrome P-450 of the controls. These results reveal differential alterations of the MFO system and the induction of one specific type of cytochrome P-450 hemoprotein.