Title of article :
Lack of initiation activity in rat liver of low doses of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline
Author/Authors :
Fukushima، نويسنده , , Shoji and Wanibuchi، نويسنده , , Hideki and Morimura، نويسنده , , Keiichirou and Wei، نويسنده , , Min and Nakae، نويسنده , , Dai and Konishi، نويسنده , , Yoichi and Tsuda، نويسنده , , Hiroyuki and Takasuka، نويسنده , , Nobuo and Imaida، نويسنده , , Katsumi and Shirai، نويسنده , , Tomoyuki and Tatematsu، نويسنده , , Masae and Tsukamoto، نويسنده , , Tetsuya and Hirose، نويسنده , , Masao and Furukawa، نويسنده , , Fumio، نويسنده ,
Abstract :
It has been generally accepted that genotoxic carcinogens have no threshold in exerting their potential for cancer induction. However, the non-threshold theory can be challenged for cancer risk assessment in humans. Here we examined low dose carcinogenicity of a food-derived, genotoxic hepatocarcinogen, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), using an in vivo medium-term bioassay to detect initiating activity for rat hepatocarcinogenesis. With MeIQx initiation at various doses followed by administration of phenobarbital, a well known hepatopromoter, no induction of glutathione S-transferase placental form-positive foci, assessed as preneoplastic lesions, was noted at doses of 0.001–1 ppm. The results imply a no-observed effect level for hepatocarcinogenicity with this genotoxic agent.
Keywords :
Low dose carcinogenicity , 5-f]quinoxaline , Phenobarbital , 2-Amino-3 , risk assessment , Carcinogenicity threshold
