CARCINOGENICITY OF THE HAIR-DYE COMPONENT 2-NITRO-PARA-PHENYLENEDIAMINE - INDUCTION OF EOSINOPHILIC HEPATOCELLULAR NEOPLASMS IN FEMALE B6C3F1-MICE

Groups of 50 male and 50 female B6C3F1 mice were given 2-nitro-p-phenylenediamine in the feed at either 2200 or 4400 ppm for 78 wk. Twenty animals of each sex were used as controls. Treatment was followed by a 12-13 wk observation period. There was a dose-related depression of body-weight gain in both sexes. Pigmentation was observed in liver, spleen, intestine and thyroid. Female mice receiving 2-nitro-p-phenylenediamine showed a dose-related increase in the incidence of hepatocellular neoplasms. The majority of these neoplasms were multiple eosinophilic hepatocellular adenomas which were different from the adenomas in control mice. A few female mice given 2-nitro-p-phenylenediamine had foci of cellular alteration in the liver. Neoplasms similar to those induced by 2-nitro-p-phenylenediamine have been reported in mice exposed to two other aromatic amines, 4-chloro-m-phenylenediamine and 4-nitro-o-phenylenediamine. However the latter did not prove to be carcinogenic. © 1971.