title: Methylated purines in human liver DNA after probable dimethylnitrosamine poisoning.
abstract: DNA, isolated from two samples of human liver obtained from a suspected dimethylnitrosamine poisoning, contained 1363 to 1373 micromol of 7-methylguanine per mol of guanine and 273 to 317 micromol of O6-methylguanine per mol of guanine. Liver and kidney DNA obtained from unrelated cases contained no detectable methylated purines. From the DNA methylation levels, it is estimated that the dimethylnitrosamine-poisoning victim had been exposed to a dose of 20 mg or more of dimethylnitrosamine per kg of body weight. The results indicate for the first time that humans, like rodents, appear to activate dimethylnitrosamine metabolically to a strong methylating agent, resulting in methylation of liver DNA at both the 7- and O6 positions of guanine.
mesh_terms: D000328:Adult; D002853:Chromatography, Liquid; D004247:DNA / Q000032:analysis*; D004128:Dimethylnitrosamine / Q000506:poisoning*; D006147:Guanine / Q000032:analysis; D006801:Humans; D008099:Liver / Q000032:analysis*; D008297:Male; D008745:Methylation; D011687:Purines / Q000032:analysis*
chemical_list: D011687:Purines; D006147:Guanine; D004247:DNA; D004128:Dimethylnitrosamine