The effect of manganese and ferric ions on the in vitro formation of dihydrodihydroxy metabolites of benzo(a)pyrene.
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.
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
D001580:Benzopyrenes; D005290:Ferric Compounds; D008345:Manganese; D007501:Iron