INDUCTION OF DNA DAMAGE BY DIMETHYLARSINE, A METABOLITE OF INORGANIC ARSENICS, IS FOR THE MAJOR PART LIKELY DUE TO ITS PEROXYL RADICAL

To reveal the mechanisms of previously reported lung-specific DNA strand scissions in murine after oral administration of dimethylarsinic acid (DMAA), a main metabolite of inorganic arsenics in mammals, the ultimate substance causing DNA lesion was investigated using dimethylarsine which was a further metabolite of DMAA. The alkaline elution assay using 3H-labeled DNA showed that a major portion of the strand breaks was not suppressed by SOD and catalase, suggesting an ultimate substance other than active oxygen participated in the DNA damage. By ESR analysis, a radical estimated to be (CH3)2AsOO· was detected as a reaction product of dimethylarsine and molecular oxygen. This peroxyl radical, rather than active oxygen, was assumed to play a major role in DNA damage. © 1990.