Induction of tumors in the Zymbal gland, oral cavity, colon, skin and mammary gland of F344 rats by a mutagenic compound, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline.

A mutagenic compound, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, which was first isolated from broiled sardines and was shown to be carcinogenic to mice, was also found to be carcinogenic to F344 rats. It induced tumors in various organs, such as the Zymbal gland, oral cavity, colon, skin and mammary gland of male and female rats when given at 0.03% in the diet. However, it was noteworthy that tumors were not observed in the liver. Most of the tumors in the Zymbal gland, oral cavity and skin were squamous cell carcinomas, and most of the mammary gland tumors were adenocarcinomas. The colon tumors were identified as adenomas or adenocarcinomas. In control rats no tumors developed in these organs during the 40-week experiment.