title: The effect of manganese and ferric ions on the in vitro formation of dihydrodihydroxy metabolites of benzo(a)pyrene.
abstract: The effect of ferric and manganese ions on the in vitro metabolism of benzo(a)pyrene (BP) to dihydrodihydroxy (diol) metabolites by rat liver microsomal preparations was studied. Of the 3 diols separated by high-pressure liquid chromatography (HPLC) and called diols 1, 2 and 3 in order of elution, diol 1 was identified by its U.V. spectrum as the 9,10-diol; diols 2 and 3 have not yet been identified positively but are probably the 4,5- and 7,8-diols respectively. Higher concentrations of both metals altered the diol profile; 10 and 50 mumol Fe3+ per incubation caused the disappearance of diols 1 and 2 and an increase in diol 3; 10 mumol Mn2+ caused a significant decrease in diol 2 while 50 mumol reduced diol 2 to a negligible amount and inhibited the formation of diol 1; both concentrations caused a relative increase in diol 3. If the tentative identification of diol 3 as the 7,8-diol is correct, manganese and ferric ions could be significant in the metabolism of BP to the active metabolite, the 7,8-diol-9,10-epoxide.
mesh_terms: D000818:Animals; D001580:Benzopyrenes / Q000032:analysis / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D005290:Ferric Compounds / Q000494:pharmacology*; D066298:In Vitro Techniques; D007501:Iron / Q000494:pharmacology*; D008345:Manganese / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000378:metabolism*; D051381:Rats
chemical_list: D001580:Benzopyrenes; D005290:Ferric Compounds; D008345:Manganese; D007501:Iron