Detection of 1,N2-propanodeoxyguanosine adducts of 2-hexenal in organs of Fischer 344 rats by a 32P-post-labeling technique.
2-Hexenal is an alpha,beta-unsaturated carbonyl compound which is mutagenic, genotoxic and forms cyclic 1,N2-propanodeoxyguanosine adducts like similar propenals for which carcinogenicity was shown, e.g. acrolein or crotonaldehyde. Since humans have a permanent intake of 2-hexenal via vegetarian food this genotoxic compound is considered to play a role in human carcinogenicity. The data base is, however, presently not sufficient for a cancer risk assessment. To date no long term carcinogenicity study on 2-hexenal has been published. Detection of respective DNA adducts of this substance in animals or humans could allow cancer risk assessment. Therefore, we have developed a 32P-post-labeling technique based on nuclease P1 enrichment and TLC separation of the labeled adducts. The respective adducts are stable over a wide pH range from pH 4 to pH 11 and relatively stable against nuclease P1. The detection limit was 0.03 adducts per 10(6) nucleotides and the recovery was 10%. With this method we have shown in vivo formation of 1,N 2-propanodeoxyguanosine adducts of 2-hexenal for the first time and found the respective DNA adducts in different organs of Fischer 344 rats after gavage of 500, 200 and 50 mg 2-hexenal/kg body wt. No adducts could be detected in the organs of untreated rats. There is a clear dependence of the adduct level and the CBI (covalent binding index) on the dose. The CBI of 2-hexenal calculated on the basis of our adduct levels is extremely low (0.06). Since intake of 2-hexenal via fruit and vegetables is very low the cancer risk from 2-hexenal intake via food must also be considered as very low according to a first raw estimation on the basis of CBI and intake. The situation deserves, however, a more precise risk assessment in the future.
Schuler
D
D
Department of Toxicology, University of Würzburg, Versbacher Str. 9, D-97078 Würzburg, Germany.
Eder
E
E
D000447:Aldehydes / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D018736:DNA Adducts / Q000378:metabolism; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004947:Esophagus / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D010761:Phosphorus Radioisotopes; D051381:Rats; D011916:Rats, Inbred F344; D014018:Tissue Distribution
D000447:Aldehydes; D018736:DNA Adducts; D010761:Phosphorus Radioisotopes; C060934:1,N(2)-propanodeoxyguanosine; C051750:2-hexenal; D003849:Deoxyguanosine