Formation of 8-hydroxyguanine residues in cellular DNA exposed to the carcinogen 4-nitroquinoline 1-oxide.

8-Hydroxyguanine (8-OH-Gua) residues were formed in DNA of Ehrlich ascites cells exposed to the carcinogen 4-nitroquinoline 1-oxide. Formation of 8-OH-Gua was confirmed by chemical treatment of calf thymus DNA with the proximate metabolite of this carcinogen, 4-hydroxyaminoquinoline 1-oxide, together with seryl-adenosine monophosphate. The ratio of the rates of formations of 8-OH-Gua and the quinoline-bound adducts was about 0.2-0.3. A conceivable mechanism of formation of 8-OH-Gua is proposed.