EFFECTS OF LONG-TERM FEEDING WITH 2-AMINO-1-METHYL-6-PHENYLIMIDAZO[4,5-B]PYRIDINE (PHIP) IN C57BL BYA AND E-MU-PIM-1 MICE/

The heterocyclic amine PhIP, 2-amino-1-methyl-6-phenylimidazo[4,5 b] p yridine, has been shown to be carcinogenic in rats producing colon and mammary carcinomas. There is, so far, only a single long-term study r eport on PhIP carcinogenicity in mice. However, this study focuses on the lymphoma induction only. Whether PhIP induces tumors in other orga ns in mice b after long-term exposure is yet to be established. To con tribute to the knowledge about the long-term effects of PhIP feeding t he remaining animals from a 7 months feeding study (0.03% PhIP) were p ut on standard diet and followed up to 18 months. The results confirme d that PhIP is a potent mouse lymphomagen. In addition, treatment with 0.03% PhIP in the diet for the first 7 months of a life-time study (1 8 months) gave rise to very few and sporadic tumors in other tissues, indicating weak, if any, carcinogenicity of PhIP to organs other than the lymphatic system under the present study design. (C) 1998 Elsevier Science Ireland Ltd.