Development of a P-32-postlabeling method for the detection of 1,N-2-propanodeoxyguanosine adducts of 2-hexenal in vivo

2-Hexenal is an alpha,beta-unsaturated carbonyl compound which forms cyclic 1,N-2-propano adducts in vitro. The adduct formation in vivo was not repor ted by others to date. Because this type of adduct is considered promutagen ic (2-hexenal is actually mutagenic and genotoxic) and humans are permanent ly exposed to this compound via vegetarian food, 2-hexenal may play a role in carcinogenicity. To improve the cancer risk assessment, we developed a n ew P-32-postlabeling technique for this compound and optimized the differen t steps of the postlabeling procedure. The results of the postlabeling meth ods are shown. A labeling efficiency of 35%, a recovery of 10% for the synt hesized standards, and a detection Limit of three 2-hexenal adducts per 10( 8) nucleotides was achieved. After gavage of 500 mg/kg of body weight to ma le Fischer 344 rats, the respective DNA adducts were detected in rat liver DNA, With this study, we demonstrate in vivo adduct formation of 2-hexenal for the first time. Highest adduct levels were found 2 days after gavage, a nd after 4 days, the level was even higher than after 1 day. No adducts wer e detected 8 h after gavage. The respective adducts could not be found as a background in tissues of untreated rats or in calf thymus DNA at the limit of detection.