title: Methylation of guanine in vivo by the organophosphorus insecticide methamidophos.
abstract: The methylating capability of methamidophos, assayed by the formation of [7-14C]methylguanine in mouse liver, was investigated using a 14C-insecticide labelled at the O--CH3 group. Following i.p. administration of the toxicant, [7-14C]methylguanine could be isolated from liver nucleic acids of treated mice. The amount of 14C-label reached its maximum 6 h following administration of the insecticide. At maximum 14C-labelling, the amount of 7-methylguanine calculated as fraction of applied dose, was 20-22 X 10(-4) and 98-104 X -4, for DNA and RNA, respectively. The results obtained indicate also, that an appreciable amount of 14C-activity is incorporate via the C-1 pool.
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes; D004247:DNA / Q000378:metabolism*; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D008745:Methylation; D051379:Mice; D009946:Organothiophosphorus Compounds / Q000378:metabolism*
chemical_list: D002250:Carbon Radioisotopes; D007306:Insecticides; D009946:Organothiophosphorus Compounds; D006147:Guanine; C014655:methamidophos; D004247:DNA