Carcinomas of the colon in Buffalo strain rats given intraperitoneal injections of methylazoxymethanol acetate.

Buffalo strain male and female rats were given methylazoxymethanol acetate (20% solution) intraperitoneally 20 mg/kg body weight weekly for 9 weeks, and killed 27 weeks later. Carcinomas of the large intestine, predominantly in the descending colon, developed in some of the rats. The incidence was higher in male than in female rats. Polypoid carcinomas were observed more often in male rats and sessile carcinomas with metastases in the female rats. Carcinomas were not observed in organs other than the large intestine.