Bioassay of N-(1-naphthyl)ethylenediamine dihydrochloride for possible carcinogenicity.
A bioassay for the possible carcinogenicity of N-(1-naphthyl)ethylenediamine dihydrochloride was conducted using Fischer 344 rats and B6C3F1 mice. N-(1-Naphthyl)ethylenediamine dihydrochloride was administered in the feed, at either of two concentrations, to groups of 50 male and 50 female animals of each species. Twenty-five rats of each sex and 50 mice of each sex were placed on test as controls. The high and low dietary concentrations of N-(1-naphthyl)ethylenediamine dihydrochloride administered to rats and male mice were 0.1 and 0.05 percent, respectively. The high and low time-weighted average concentrations administered to female mice were, respectively, 0.3 and 0.2 percent. The compound was administered in the diet for 104 weeks, followed by an observation period of 4 weeks for high dose rats, 3 weeks for low dose rats, low dose female mice, and high dose female mice, and 1 week for high dose male mice. There were no significant positive associations between the concentrations of N-(1-naphthyl)ethylenediamine dihydrochloride administered and mortality in rats of either sex or in male mice. There was a significant positive association between concentration and mortality in female mice. In all groups, except for high dose females, adequate numbers of animals survived sufficiently long to be at risk from late-developing tumors. Mean body weight depression, in relation to controls, was apparent for both sexes of rats and mice, indicating that higher concentrations of the test chemical would not have been tolerated by these animals. In rats or mice of either sex, there were no statistically significant positive associations between the concentration of N-(1-naphthyl)ethylenediamine dihydrochloride and tumor incidence. Under the conditions of this bioassay, dietary administration of N-(1-naphthyl)ethylenediamine dihydrochloride was not carcinogenic in Fischer 344 rats or B6C3F1 mice.