Intestinal tumors in rats induced by mutagens from glutamic acid pyrolysate.

2-Amino-6-methyldipyrido[1,2-a:3',3'-d]imidazole (Glu-P-1) and 2-amino-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2), which were isolated from a glutamic acid pyrolysate, were proved to be multipotent carcinogens in rats, inducing tumors of the liver, intestine, ear duct and clitoral gland when administered orally to F344 rats. Intestinal tumors were produced for the first time in a series of experiments with heterocyclic amines. Details of the morphologic features of the intestinal tumors induced in F344 rats by Glu-P-1 and Glu-P-2 are described. There were no marked differences between the tumors induced by Glu-P-1 and Glu-P-2. Grossly, the tumors of the small intestine were recognized as papillary, polypoid or umbilicated masses. The most common tumors in the large intestine showed polypoid growth with a short stalk. Histologically, the intestinal tumors were classified as adenomas, adenocarcinomas, and mucinous carcinomas. Several adenocarcinomas were found adjacent to adenomas. Mucinous carcinomas developed only in the small intestine. Most of these tumors showed endophytic growth with extensive mucus production. Tumor tissue from the small intestine transplanted into the subcutis of the flank grew into tumors within 3 months.