Efficient method for rapid induction of aberrant crypt foci in rats with 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine.
2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) induces aberrant crypt foci (ACFs) as well as colon cancer in F344 male rats. Conditions allowing rapid development of ACFs over a short period were investigated. F344 male rats were fed 400 ppm of PhIP x HCl in a low-fat diet (LF) for 2 weeks and then given a PhIP-free, high-fat diet containing PRIMEX (HF-PR) or safflower oil, or PhIP-free LF for 4 or 12 weeks. Rats fed HF-PR for 4 weeks gave the highest number of ACFs/rat (3.3) and their size in terms of aberrant crypts/ACF (2.7) was much larger than that obtained with conventional continuous feeding of PhIP for 25 weeks in the CE-2 diet. Therefore, 2 weeks of dietary exposure to 400 ppm of PhIP x HCl, followed by HF-PR for 4 weeks, is a practical and convenient method for obtaining ACFs. This protocol should be useful for studies of the early phase of colon carcinogenesis.
Ochiai
M
M
Carcinogenesis Division, National Cancer Center Research Institute, Tokyo, Japan.
Nakagama
H
H
Watanabe
M
M
Ishiguro
Y
Y
Sugimura
T
T
Nagao
M
M
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002273:Carcinogens / Q000633:toxicity*; D003106:Colon / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000139:chemically induced*; D004041:Dietary Fats / Q000633:toxicity; D007093:Imidazoles / Q000633:toxicity*; D008297:Male; D011230:Precancerous Conditions / Q000139:chemically induced*; D051381:Rats; D011916:Rats, Inbred F344
D002273:Carcinogens; D004041:Dietary Fats; D007093:Imidazoles; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine