Cytogenetic effects of a food mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and its metabolite, 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP), on human and Chinese hamster cells in vitro

2-Amino-1-methyl-6-phenylimidazo4,5-b]pyridine (PhIP) induced structural chromosomal aberrations (CAs) and sister-chromatid exchanges (SCEs) in human lymphocytes and human diploid fibroblasts (TIG-7) at concentrations above 12.5 μg/ml in the presence of rat S9 mix. PhIP also elevated the frequencies of SCEs in human lymphocytes in the presence of rat S9 at concentrations above 2.0 μg/ml with dose-dependency. A proximate form of metabolites of PhIP, 2-hydroxyamino-1-methyl -phenylimidazo4,5-b]pyridine (N-OH-PhIP), caused CAs in human and Chinese hamster fi fibroblast cells in the absence of S9 mix at concentrations above 0.75 μg/ml and 1.25 μg/ml, respectively, which were 10 times lower than the effective concentration of PhIP. No marked differenceswere observed in the cytogenetic sensitivity to N-OH-PhIP between human and Chinese hamster cells, except between lymphocytes obtained from different donors.