[The determination of DNA adducts in liver and lung of mice exposed to dimethylnitrosamine].
The purpose of this study was to assess the role of dimethylnitrosamine (DMN) in DNA lesions and to determine the levels of O6-methyl-guanine (O6-mGua) and N-7-methyl-guanine (m7-Gua). Mice were treated with 10 ppm DMN in drinking water for 1, 2, 4, 8, 16 and 32 days. The average dosage of DMN was 2 mg/kg/day, DNA was isolated from liver and lung specimens, and its purine bases separated by high-performance liquid chromatography with fluorescence detection. The results showed the presence of O6-mGua and m7-Gua in the DNA following administration of DMN. The m7-Gua was found to be unsteady. O6-mGua decreased rapidly after 1 and 2 days treatment with DMN, but was raised after 32 days with continuous exposure. These findings suggest that damaged DNA would be repaired in vivo, but with continuous exposure to DMN, O6-mGua would accumulate in the DNA and this might be the cause of tumor induction.
Zhang
P C
PC
Department of Chemical Carcinogenesis, Guangzhou Medical College.
D000818:Animals; D004247:DNA / Q000032:analysis / Q000187:drug effects*; D004249:DNA Damage; D004128:Dimethylnitrosamine / Q000633:toxicity*; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives / Q000032:analysis; D008099:Liver / Q000032:analysis; D008168:Lung / Q000032:analysis; D008297:Male; D051379:Mice
D006147:Guanine; C008450:7-methylguanine; D004247:DNA; C008449:O-(6)-methylguanine; D004128:Dimethylnitrosamine