COMPARATIVE CARCINOGENICITY OF 4-AMINOBIPHENYL AND THE FOOD PYROLYSATES, GLU-P-1, IQ, PHIP, AND MEIQX IN THE NEONATAL B6C3F1 MALE-MOUSE

The tumorigenic activities of four representative heterocyclic amine f ood pyrolysates, 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu -P-1), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimet hylimidazo[4,5f]quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimid azo[4,5-b]pyridine (PhIP), were assessed in the neonatal male B6C3F1 m ouse and were compared with that of the potent human carcinogen, 4-ami no-biphenyl (4-ABP). These aromatic amines were administered by i.p. i njection at two dose levels on days 1, 8, and 15 after birth; and the incidence of tumors was examined at 8 and 12 months. Glu-P-1, IQ, PhIP , MeIQx, and 4-ABP each induced a significant incidence of hepatic ade nomas, as compared to the solvent-treated (DMSO) control. Hepatocellul ar carcinomas were also observed with 4-ABP, SO, and MeIQx. Overall tu morigenicity was in the order: 4-ABP > Glu-P-1 > IQ approximately PhIP > MeIQx > DMSO. In the neonatal B6C3F1 mouse, these heterocyclic arom atic amines showed potent tumorigenicity after 8 and 12 months at tota l doses that were 5-10 000-fold less than those employed in standard c hronic bioassays.