Age associated differences in effects of benzene on mixed-function oxidases in phenobarbital-treated rats.

These studies were performed on 5, 10, 30, 60 and 540 days old female Wistar rats. The animals were treated i.p. with phenobarbital (50 mg/kg body weight) and benzene (250 mg/kg body weight). In smooth (SER) and rough (RER) hepatic microsomes, the mixed function oxidases activity were studied. The earlier phenobarbital induction decreased the negative benzene influence. In all examined animals this was observed for protein, cytochrome P-450, and demethylase 4-aminopyrine activities. A partial decrease of inhibition was noticed only for activities of NADPH-cytochrome bs and NADH-cytochrome bs reductase activities, phenobarbital did not significantly change the effect of benzene.