Effect of high-fat diet on colon carcinogenesis in F344 rats treated with 1,2-dimethylhydrazine, methylazoxymethanol acetate, or methylnitrosourea.

Male inbred F344 weanling rats were fed semipurified diets containing 20 or 5% beef fats. At 7 weeks of age, all animals except controls were given 1,2-dimethylhydrazine [DMH (150 mg/kg body weight s.c.; one dose)], methylazoxymethanol acetate [MAM acetate (35 mg/kg body weight i.p.; one dose)], or methylnitrosourea (2.5 mg/rat/week intrarectally; two doses), and autopsied 35 weeks later. No major differences were observed in the frequency (number of rats with tumor) of DMH- or MAM acetate-induced duodenal, ear duct, and kidney tumors between the rats fed diets containing 20 or 5% fat. However, the animals fed the diet containing 20% fat had slight although not statistically significant influence on the incidence of adenomas and adenocarcinomas in the colon.