Alkylation of DNA by organophosphorus pesticides

Methods for the detection of in vivo alkylation of nucleic acids are discussed. Alkylation of mammalian DNA at N-7 of guanine provides the most sensitive and least equivocal evidence of methylation by an exogenous chemical or its metabolite. No 7-methylguanine was detected in the combined DNA from the lungs, livers, hearts, brains, kidneys, testes and spleens from 20 rats exposed to 0.064 micrograms l-1 of [Me-14C]-dichlorvos at a specific radioactivity of 113 Ci mol-1 for 12 hrs.