title: Bioassay of 1-amino-2-methylanthraquinone for possible carcinogenicity (CAS No. 82-28-0).
abstract: A bioassay for possible carcinogenicity of technical-grade 1-amino-2-methylanthraquinone was conducted using Fischer 344 rats and B6C3F1 mice. 1-Amino-2-methylanthraquinone was administered in the feed, at either of two concentrations, to groups of 45 to 50 males and females of each species. The high and low time-weighted average concentrations of 1-amino-2-methylanthraquinone were 0.20 and 0.10 percent, respectively, for male and female rats. For mice, two dosage regimens (designated A and B) were used, but the time-weighted average concentrations were the same, 0.06 percent. For each species, 50 animals of each sex were placed on test as controls. The period of compound administration was 78 weeks for rats followed by 26 to 28 additional weeks of observation, and 73 weeks for mice followed by 24 to 25 additional weeks of observation. A statistically significant positive association between compound administration and mortality was established for the male and female dose A mice. Dose A mice did not survive sufficiently long to be at risk from late-developing tumors. Survival in all other groups was adequate. The incidence of hepatocellular carcinomas was statistically significant among dosed rats of both sexes. Kidney neoplasms (the combined incidence of tubular-celladenomas, tubular-cell adenocarcinomas, and adenocarcinomas NOS) were significantly increased among dosed male rats. Administration of the compound was associated with a significant increase in the combined incidence of hepatocellular carcinomas and neoplastic liver nodules in female mice. No other neoplasms occurred in statistically significant positive incidences in male or female mice. 1-Amino-2-methylanthraquinone demonstrated nephrotoxic properties in mice of both sexes. Under the conditions of this bioassay, 1-amino-2-methylanthraquinone was carcinogenic in Fischer 344 rats, inducing hepatocellular carcinomas in rats of both sexes, and kidney tumors in male rats. The compound was carcinogenic in female B6C3F1 mice, producing an increased combined incidence of hepatocellular carcinomas and neoplastic nodules.