[Function of the liver monooxygenase system after exposure to ionol and polychlorinated biphenyls]

After a single administration of polychlorinated diphenyls (sovol) at a dose of 50 mg/kg content of hemoproteins was increased simultaneously with an increase in the rate of N- and O-demethylation in rat liver microsomes. Repeated administrations of a synthetic antioxidant 2,6-ditret-butyl-4-methylphenol (ionol) at a dose of 500 mg/kg stimulated also the liver tissue monooxygenase system; in this case, an increase in content of cytochromes P-450 and b5 was accompanied by a distinct acceleration in oxidation of the first and second types of substrates in microsomes. A combined effect of sovol and ionol maintained the rate of microsomal enzymes induction, which exceeded markedly the values caused by individual effects of the compounds.