Formation of DAN-binding products from isolated benzo[a]pyrene metabolites in rat liver nuclei

Liver nuclei from 3-methylcholanthrene-treated rats in the presence of NADPH metabolized 3- and 9-hydroxybenzoa]pyrene and 7,8-dihydro-7,8-dihydroxybenzoa]pyrene to products that bound to DNA. Maximal binding was obtained with the dihydrodiol which was approximately 3-fold that with 9-hydroxybenzoa]pyrene, and 60-fold that with 3-hydroxybenzoa]pyrene, as substrates. Both 4,5-dihydro-4,5-dihydroxybenzoa]pyrene and 9,10-dihydro-9,10-dihydroxybenzoa]pyrene were also extensively metabolized by the nuclear fraction but did not give rise to DNA-binding products.The available evidence suggests that the DNA binding species derived from 9-hydroxy-benzoa]pyrene is 9-hydroxy-benzoa]pyrene-4,5-oxide and from 7,8-dihydro-7,8-dihydroxybenzoa]pyrene, as previously observed in different systems, 7,8-dihydro-7,8-dihydroxy-benzoa]pyrene-9,10-oxide.