Stula Ef, H. Sherman, Zapp Ja
1975
Citations
2
Influential Citations
76
Citations
Quality indicators
Journal
Toxicology and applied pharmacology
Abstract
Abstract The primary purpose of these experiments was to investigate the carcinogenic potential of 4,4′-methylene-bis(2-chloroaniline) for the rat. Because two structurally related aromatic amines, 3,3′-dichlorobenzidine and 4,4′-methylene-bis(2-methylaniline), had already been shown to be carcinogenic for the rat, they were included as positive controls. After these studies were in progress, it was reported that 4,4′-methylene-bis(2-chloroaniline) was carcinogenic for rats fed a protein-deficient diet. Consequently, a group of rats on the same deficient diet was added to evaluate the effect of diet. Rats were fed for 2 years diets containing 1000 ppm of each test substance except 4,4′-methylene-bis(2-methylaniline), which was fed at 200 ppm. 3,3′-Dichlorobenzidine at a level of 1000 ppm in a standard diet produced tumors of the mammary gland in rats of both sexes, together with Zymbal gland and hematopoietic tumors in males. The same level of 4,4′-methylene-bis(2-chloroaniline) in a standard diet produced tumors of the lung in rats of both sexes. By comparison, in a protein-deficient diet 4,4′-methylene-bis(2-chloroaniline) caused lung tumors in the experimental animals of both sexes, liver tumors in males, and malignant mammary tumor in females. 4,4′-Methylene-bis(2-methylaniline) at a level of 200 ppm in a standard diet produced tumors in the liver in rats of both sexes together with skin and mammary tumors in males. These chemicals are not known to have caused neoplasia in man to date.