Further metabolism of diol-epoxides of chrysene and dibenz[a,c]anthracene to DNA binding species as evidenced by 32P-postlabelling analysis

Incubation of r-1t-2-dihydroxy-t-3,4-oxy-1,2,3,4-tetrahydro-chrysene (anti-chrysene-1,2-diol 3,4-oxide), the bay-region diol-epoxide of chrysene, with rat liver microsomes in the presence of NADP+ and DNA, followed by 32P-postlabelling analysis of the DNA, revealed the presence of at least two adducts not detected when anti-chrysene-1,2-diol 3,4-oxide was incubated with DNA alone. The formation of these adducts was not blocked by the epoxide hydrolase inhibitor 1,1,1-trichloropropane-2,3-oxide. One of the adducts cochromatographed with the adduct spot obtained when authentic 9-hydroxy-r-1,t-2-dihydroxy-t-3,4-oxy-1,2,3,4-tetra-hydrochrysene (anti-9-OH-chrysene-1,2-diol 3,4-oxide) was reacted with DNA. Evidence suggested that a second adduct could also be formed by further metabolism of anti-9-OH- chrysene-1,2-diol 3,4-oxide. In addition, evidence was obtained for the further metabolism of the syn-isomer of chrysene 1,2-diol 3,4-oxide and the anti-isomers of a non-bay-region diol epoxide of dibenz[a,c]anthracene to DNA binding species, but not for that of either the anti- or syn- isomers of the bay-region diol-epoxide of benzo[a]pyrene, the anti-isomers of the bay-region or a non-bay-region diol-epoxide of benz[aanthracene, or the anti-isomer of the bay-region diol-epoxide of benzo[bfluoranthene.