title: In vivo alkylation studies with dichlorvos at practical use concentrations.
abstract: Twenty male CFE rats were exposed to atmospheres containing 0.064 microgram/l of [Me-14C] dichlorvos (113 Ci/mol) for 12 h. Analysis of the DNA and RNA from the total soft tissues of these rats revealed no methylation of the N7 atom of guanine moieties. The limits of detection of methylation were one methyl group per 6.0 X 10(11) and per 2 X 10(9) nucleotide units for DNA and RNA, respectively. Only 0.000001% of the administered dose would have needed to react with DNA in order to produce detectable methylation of this macromolecule. The exposure period employed in this study (12 h) constituted a significant fraction of the half-life of 7-methylguanine moieties in DNA (3 days). On the basis of this information and the extremely rapid metabolism of dichlorvos in a wide range of mammalian tissues and species it was concluded that dichlorvos does not methylate the nucleic acids of mammalian tissues when it is inhaled continuously at practical use concentrations.
mesh_terms: D000477:Alkylating Agents; D000818:Animals; D002854:Chromatography, Paper; D004247:DNA / Q000378:metabolism; D004006:Dichlorvos / Q000494:pharmacology*; D006147:Guanine / Q000378:metabolism; D006868:Hydrolysis; D008297:Male; D013058:Mass Spectrometry; D008745:Methylation; D011506:Proteins / Q000378:metabolism; D011687:Purines / Q000652:urine; D012313:RNA / Q000378:metabolism; D051381:Rats
chemical_list: D000477:Alkylating Agents; D011506:Proteins; D011687:Purines; D006147:Guanine; D012313:RNA; D004006:Dichlorvos; D004247:DNA