title: Formation, persistence, and identification of DNA adducts formed by the carcinogenic environmental pollutant o-anisidine in rats.
abstract: 2-Methoxyaniline (o-anisidine) is an industrial and environmental pollutant causing tumors of urinary bladder in rodents. Here, we investigated the formation and persistence of DNA adducts in the Wistar rat. Using the (32)P-postlabeling method, three o-anisidine-derived DNA adducts were found in several organs of rats treated with a total dose of 0.53 mg o-anisidine/kg body wt (0.15, 0.18, and 0.2 mg/kg body wt ip in the first, second, and third day, respectively), of which the urinary bladder had the highest levels. At four posttreatment times (1 day, 13 days, 10 weeks, and 36 weeks), DNA adducts in bladder, liver, kidney, and spleen of rats were analyzed to study their persistence. In all time points, the highest total adduct levels were found in urinary bladder (39 adducts per 10(7) nucleotides after 1 day and 15 adducts per 10(7) nucleotides after 36 weeks) where 39% adducts remained. In contrast to the urinary bladder, no persistence was detected in other organs. All three DNA adducts were identified as deoxyguanosine adducts. When deoxyguanosine was reacted with the oxidative metabolite of o-anisidine, N-(2-methoxyphenyl)hydroxylamine, three adducts could be separated by high-performance liquid chromatography (HPLC) and were identified by mass spectroscopy and/or nuclear magnetic resonance spectrometry. All adducts are products of the nitrenium/carbenium ions, the reactive species generated from N-(2-methoxyphenyl)hydroxylamine. The major adduct was identified to be N-(deoxyguanosin-8-yl)-2-methoxyaniline. Using cochromatography on HPLC, this adduct was found to be identical to the major adduct generated by activation of o-anisidine in vitro and in vivo.
authors.affiliation: Department of Biochemistry, Faculty of Science, Charles University, 128 40 Prague 2, Czech Republic.
authors.forename: Karel
authors.initials: K
authors.lastname: Naiman
authors.forename: Martin
authors.initials: M
authors.lastname: Dracínský
authors.forename: Petr
authors.initials: P
authors.lastname: Hodek
authors.forename: Markéta
authors.initials: M
authors.lastname: Martínková
authors.forename: Heinz H
authors.initials: HH
authors.lastname: Schmeiser
authors.forename: Eva
authors.initials: E
authors.lastname: Frei
authors.forename: Marie
authors.initials: M
authors.lastname: Stiborová
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism / Q000633:toxicity*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D018736:DNA Adducts / Q000378:metabolism*; D003849:Deoxyguanosine / Q000378:metabolism; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity*; D006898:Hydroxylamines / Q000378:metabolism; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization; D013154:Spleen / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution; D001743:Urinary Bladder / Q000187:drug effects / Q000378:metabolism
chemical_list: D000814:Aniline Compounds; D018736:DNA Adducts; D004785:Environmental Pollutants; D006898:Hydroxylamines; C569872:N-(2-methoxyphenyl)hydroxylamine; D003849:Deoxyguanosine; C003898:2-anisidine