Differential localization of microsomal mixed function oxidase activity in periportal and perivenous hepatocytes isolated from rat liver.

1. The activity per mg of microsomal protein of aminopyrine N-demethylase was higher in perivenous (PV) than in periportal (PP) hepatocytes of rat, but when it was expressed per cytochrome P-450 content the difference in the activity was not significant. 2. The activity of 7-ethoxycoumarin O-deethylase, when expressed per mg protein and per P-450 content, was significantly higher in PV than in PP cells. 3. The activities of dimethylnitrosamine(DMNA) N-demethylase and aniline p-hydroxylase were not significantly different between two subpopulations of isolated hepatocytes when either expressed per mg protein or per P-450 content.