title: Existence of no-observed effect levels for 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline on hepatic preneoplastic lesion development in BN rats.
abstract: There is increasing evidence that dose-response curve of genotoxic carcinogen is nonlinear and a practical threshold dose exists. However, little is known about differences in the dose-response relationship of genotoxic carcinogen among different strain rats. Herein, we showed that low doses of genotoxic carcinogen 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx) had no effects on induction of liver glutathione S-transferase placental form (GST-P)-positive foci in both BN and F344 rats, and therefore demonstrated the existence of no-observed effect level for hepatocarcinogenicity of this genotoxic carcinogen irrespective of strains. These findings further support our notion that a practical threshold dose for MeIQx hepatocarcinogenicity exists in rats.
authors.affiliation: Department of Pathology, Osaka City University Medical School, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.forename: Taka-Aki
authors.initials: TA
authors.lastname: Hori
authors.forename: Toshio
authors.initials: T
authors.lastname: Ichihara
authors.forename: Hideki
authors.initials: H
authors.lastname: Wanibuchi
authors.forename: Keiichirou
authors.initials: K
authors.lastname: Morimura
authors.forename: Jin Seok
authors.initials: JS
authors.lastname: Kang
authors.forename: Rawiwan
authors.initials: R
authors.lastname: Puatanachokchai
authors.forename: Shoji
authors.initials: S
authors.lastname: Fukushima
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D051549:Glutathione S-Transferase pi / Q000378:metabolism*; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced* / Q000201:enzymology; D008297:Male; D019055:No-Observed-Adverse-Effect Level; D011230:Precancerous Conditions / Q000139:chemically induced* / Q000201:enzymology; D011810:Quinoxalines / Q000633:toxicity*; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344
chemical_list: D002273:Carcinogens; D011810:Quinoxalines; C036990:2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline; D051549:Glutathione S-Transferase pi