Ethoxyquin feeding to rats increases liver microsome-catalyzed formation of benzo(a)pyrene diol epoxide--DNA adduct.

Abstract The ability of rat liver microsomes to catalyze the formation of benzo(a)pyrene 7,8-diol-9,10-epoxide — DNA nucleoside adduct was increased threefold by feeding 0.5% ethoxyquin to the animals. Microsomal epoxide hydratase activity was enhanced i parallel by a factor of 3 while aryl hydrocarbon hydroxylase activity was not induced. Liver microsomes from rat pretreated with 3-methylcholanthrene produced an increased proportion of diol epoxide — DNA adduct when ethoxyquin had been fed to the animals. The main chromatographic peak formed by microsomes from 3-methylcholanthrene treated rats which contains DNA adducts of secondary benzo(a)pyrene phenol metabolites is reduced when the ani…