Abstract
The four 2''-deoxyribonucleosides were γ-irradiated or were aerobically treated with Fenton-type-reagents, Fe(II)-EDTA or a renal carcinogen Fe(II)-nitrilotriacetic acid (NTA) under the neutral conditions. The reaction mixtures were immediately analyzed by reverse-phase HPLC. Major products detected were 2-hydroxydeoxyadenosine (2-OH-dA), 8, 5''-cyclodeoxyadenosine (cyclo-dA), 8-hydroxydeoxyadenosine (8-OH-dA), 5-formyldeoxyuridine (5-CHO-dU), 5-hydroxydeoxycytidine (5-OH-dC), 8-hydroxydeoxyguanosine (8-OH-dG), 8, 5''-cyclodeoxyguanosine (cyclo-dG), and glyoxal and its adduct with dG. Ratio of these oxidized products were dramatically changed depending upon the agents used. For example, 2-OH-dA was a modified nucleoside produced most efficiently by Fe(II)-EDTA, while 5-CHO-dU and 5-OH-dC were the major products by the Fe(II)-NTA treatment and γ-irradiation, respectively. Glyoxal itself was estimated to be produced most frequently (13 folds of 8-OH-dG) when treated with Fe(II)-EDTA, but its formation was not detected by the treatment with Fe(II)-NTA or by γ-irradiation. 8-OH-dA was not produced by Fe-EDTA or Fe-NTA but was produced by γ-irradiation. In contrast, 2-OH-dA was not produced by γ-irradiation. These results suggest that triphosphates of 2-OH-dA, cyclo-dA, 8-OH-dA, cyclo-dG, 5-CHO-dU, 5-OH-dC, and glyoxal-dG as well as 8-OH-dG may be produced in cells with different ratio by various types of oxidative stress and involved in mutagenesis and carcinogenesis.
