Metabolism of benz[j]aceanthrylene (cholanthrylene) and benz[l]aceanthrylene by induced rat liver S9

The metabolites of benz[j]aceanthrylene (B[j]A) produced by incubation with liver S9 proteins from rats induced with Aroclor-1254 and phenobarbital have been identified as: trans-B[j]A-1,2-dihydrodiol, B[j]A-9,10-dihydrodiol, B[j]A-11,12-dihydrodiol, and 10-hydroxy-B[j]A. The major metabolite formed (58-60%) by both induced S9 preparations was trans-B[j]A-1,2-dihydrodiol, the cyclopenta-ring dihydrodiol while oxidation at the k-region or the proximal-bay region was minor. There were no statistical differences in individual or total B[j]A metabolite rates between the 2 induced S9 preparations. B[l]A was metabolized by Aroclor-1254 and phenobarbital induced rat liver S9 preparations to trans-B[l]A-1,2-dihydrodiol, B[l]A-7,8-dihydrodiol, and B[l]A-4,5-dihydrodiol. The major B[l]A metabolite formed (28-40%) by both induced S9 preparations was B[l]A-7,8-dihydrodiol, the k-region dihydrodiol. Cyclopenta-ring oxidation to trans-B[l]A-1,2-dihydrodiol was approximately 50% of that observed for k-region oxidation. Both induced S9s produced similar rates of B[l]A metabolites except for B[l]A-7,8-dihydrodiol formation which was higher for Aroclor-1254-induced S9.