title: DNA ethylation in target and non-target organs of hamsters and rats treated with diethylnitrosamine.
abstract: Kinetics of ethylation of target and non-target organ DNA in vivo by diethylnitrosamine (DEN) was compared in rats and Syrian golden hamsters, since published reports indicate a single dose of DEN induces both kidney and liver tumors in rats and almost exclusively respiratory tract tumors in hamsters. Following treatment with 200 mg DEN/kg, 7-ethylguanine (7-etG) was lost more rapidly from hamster than from rat liver DNA, while O6-ethylguanine (O6-etG) persisted longer in hamster than in rat liver DNA. DNA ethylation was not detected in rat lung (non-target organ), while both 7-etG and O6-etG were quantitated in hamster lung (target organ) following DEN treatment. DNA ethylation in rat kidney DNA was approximately 1/10 of that in liver by 200 mg DEN/kg, and the persistence of 7-etG and O6-etG differed only slightly in these tissues. Ethylation of hamster liver DNA by DEN at doses between 20 and 200 mg/kg, as measured by 7-etG and O6-etG was proportional to the dose of carcinogen up to 160 mg/kg; at larger doses DNA ethylation sharply increased. Differences in the persistence of O6-etG between DEN-treated rats and hamsters cannot solely account for species differences in the organotropism of DEN carcinogenesis.
mesh_terms: D000478:Alkylation; D000818:Animals; D006224:Cricetinae; D004247:DNA / Q000378:metabolism*; D004260:DNA Repair; D004052:Diethylnitrosamine / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D008647:Mesocricetus; D009602:Nitrosamines / Q000378:metabolism*; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity
chemical_list: D009602:Nitrosamines; D004052:Diethylnitrosamine; D004247:DNA