ABSTRACT
Groups of male and female beagle dogs were given daily doses of 400 mg of various mixtures of naphthylamines for up to 109 months. Survivors were killed at 128 months. A variety of pathological conditions was diagnosed, but the only effect related to treatment was the induction of bladder neoplasms. All dogs which received pure 2-naphthylamine developed transitional-cell carcinomas of the bladder within 34 months. Two of 8 dogs receiving 6% 2-naphthylamine in 1-naphthylamine developed early carcinoma and 2/8 dogs receiving 0.5% 2-naphthylamine in 1-naphthylamine developed haemangioma of the bladder. Some of the dogs receiving 1-naphthylamine (total dose 950 g) and the controls had focal cystitis or hyperplasia, but no neoplasia of the bladder. These results confirm the carcinogenicity of 2-naphthylamine to dogs. No carcinogenic effect of 1-naphthylamine was observed, indicating that it is at least 200 times less potent as a carcinogen than 2-naphthylamine. The incidence of bladder cancer in dogs fed mixtures of both naphthylamines explains why previous experimental and epidemiological studies of impure 1-naphthylamine have revealed carcinogenicity.
Subject(s)
Carcinoma, Transitional Cell/chemically induced , Naphthalenes/toxicity , Urinary Bladder Neoplasms/chemically induced , 1-Naphthylamine/toxicity , 2-Naphthylamine/toxicity , Animals , Carcinoma, Transitional Cell/pathology , Dogs , Dose-Response Relationship, Drug , Female , Male , Urinary Bladder/pathology , Urinary Bladder Neoplasms/pathologyABSTRACT
The feeding of pirimicarb (2-dimethylamino-5,6-dimethylpyrimidin-4-yl dimethylcarbamate) to normal beagle dogs resulted in anaemia in a small number of animals. Dosing studies confirmed pirimicarb as the causative agent and the anaemia was characterised as haemolytic. Serological tests revealed the presence of an IgG antibody active only in the presence of pirimicarb. The level of antibody detected was related to the dose of pririmicarb given.
