Five studies of the carcinogenicity of the chlorinated pesticide Kepone (chlordecone) in animals were reviewed. Examination of histological sections showed that Kepone is unmistakably carcinogenic in rats and mice. Kepone induced malignant tumors in the liver of rats and mice in the National Cancer Institute studies and in the liver in rats in the Medical College of Virginia study. Malignant tumors were also found in organs other than the liver rats, including those on the lowest dose, in both studies. Female rats given Kepone were more likely to develop malignant tumors than male rats. There also were toxic changes, particularly in male rats. These included interstitial fibrosis of the kidney; polyarteritis of the mesenteric, pancreatic, and other arteries; and atrophy of the testes. Such lesions generally interfere with the health of the rats and with the development of tumors. Atrophy of the testes also prevents reproduction.

Animals↗

PubMedDate not supplied

Failure of methapyrilene to induce tumors in hamsters or guinea pigs.

In a small-scale experiment, 12 male and 12 female strain 2 guinea pigs were treated by gavage twice a week for 78 wk with a 200-mg/kg body weight dose of methapyrilene hydrochloride dissolved in water, a total dose of approximately 30 g/kg body weight. By the end of the treatment more than half of the animals were still alive: survivors were killed at 132 wk. A group of 20 male Syrian golden hamsters was treated twice a week by gavage with 15 mg methapyrilene hydrochloride for 58 wk, a total dose of approximately 15 g/kg body weight. Thirteen animals survived an acute convulsant effect, and the last 4 were killed at wk 61. There was no significant incidence of any tumor that could be attributed to the treatment in either guinea pigs or hamsters.

Aminopyridines↗

PubMedDate not supplied

Histopathology of carcinomas of the liver in mice ingesting dieldrin or aldrin.

C3HeB/Fe male and female mice, ingesting 10 ppm of the pesticides dieldrin or aldrin in the diet, developed highly significant incidences of carcinomas of the liver. The carcinomas varied from well differentiated to poorly differentiated and undifferentiated and were capable of metastasis.

Adenoma, Bile Duct↗

PubMedDate not supplied

Morphologic and biologic correlation of hyperplastic and neoplastic renal lesions occurring in Buffalo and Fischer strain rats ingesting n-4-(4'-fluorobiphenyl) acetamide.

Hyperplastic and neoplastic lesions of the kidney induced in inbred Buffalo and Fisher strain rats with 0.04% N-4-(4'-fluorobiphenyl) acetamide were transplanted s.c. to rats of the same strain. Hyperplastic renal lesions ("areas" or nodules) did not survive and grow. Carcinomas of the kidney grew and killed the animals. Growth was related to the size and the degree of differentiation of the carcinoma. It is concluded that the histologic pattern of hyperplastic and neoplastic lesions of the kidney can be correlated with the results obtained on transplantation.

Acetamides↗