Tumor induction in intact and regenerating liver of adult rats by a single treatment with methylazoxymethanol acetate.

Methylazoxymethanol (MAM) acetate was given once i.p. to intact adult rats and to rats at 24 h after partial hepatectomy. In each group, tumors developed as early as 10 months. The incidence of neoplastic nodules and of hepatocellular carcinomas in the carcinogen-treated intact adult rats was approximately 70% and, in the rats treated after partial hepatectomy, it was approximately 80%. The data suggest that both dividing and resting liver cells are sensitive to the tumor-initiating effects of methylazoxymethanol acetate.