title: Persistence of methylated bases in ribonucleic acid of syrian golden hamster liver after administration of dimethylnitrosamine.
abstract: 1. Syrian golden hamster liver ribosomal RNA was isolated up to 96 h after administration of [14C]dimethylnitrosamine at 25 mg/kg or 2.5 mg/kg body weight. 2. The chemical alkyation products, 7-methylguanine, 3-methylcytosine, O6-methylguanosine and 1-methyladenosine, were measured after acidic or enzymic hydrolysis of the RNA to bases or mononucleosides followed by ion-exchange chromatography. 3. Between 7 and 96 h, the relative amounts of alkylation products did not change with time even though the absolute amounts fell by approx. 80% and 51% after the high and low doses respectively. 4. The results suggest that base specific excision repair does not exist for RNA alkylation products in this experimental system.
mesh_terms: D000478:Alkylation; D000818:Animals; D002852:Chromatography, Ion Exchange; D006224:Cricetinae; D004128:Dimethylnitrosamine / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008647:Mesocricetus; D008745:Methylation; D009602:Nitrosamines / Q000494:pharmacology*; D009705:Nucleosides / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000378:metabolism*; D013997:Time Factors
chemical_list: D009602:Nitrosamines; D009705:Nucleosides; D012335:RNA, Ribosomal; D004128:Dimethylnitrosamine