Comparison of in vivo and in vitro binding of polycyclic hydrocarbons to DNA.
The in vivo binding of [3H]benzo(a)pyrene (BP) and 3-[3H]methylcholanthrene (3MC) to liver and lung DNA was studied in A/J mice. Only in liver was there any reduction in total DNA-bound radioactivity between 4 h and 24 h after administration of the hydrocarbon. DNA was fractionated on Sephadex LH-20 after enzymatic digestion. A single deoxyribonucleoside-BP adduct was detected whereas two major 3MC-adducts were observed. Wtih both BP and 3MC, three additional peaks of radioactivity eluted rapidly in the lung DNA experiments while a fourth was noted with liver DNA. The nucleoside-bound adducts from lung represented a much larger proportion of the total radioactivity than with liver. In vitro analysis of 3MC binding to DNA showed the nucleoside-bound adducts to be predominantly deoxyguanosine-dependent but that the early peaks were independent of base suggesting binding to another part of the DNA molecule, perhaps phosphate, i.e, phosphotriesters.
D000818:Animals; D001580:Benzopyrenes / Q000378:metabolism; D002850:Chromatography, Gel; D004247:DNA / Q000378:metabolism*; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D008748:Methylcholanthrene / Q000378:metabolism; D051379:Mice; D008805:Mice, Inbred A; D011083:Polycyclic Compounds / Q000378:metabolism*
D001580:Benzopyrenes; D011083:Polycyclic Compounds; D008748:Methylcholanthrene; D004247:DNA