1-Amino-2-methylanthraquinone,an intermediate in the synthesis of anthraquinone dyes and a dye itself, wasselected for bioassay by the National Cancer Institute in an attempt toelucidate those chemicals which may be responsible for the increasedincidenceof bladder cancer observed among workers in the dye manufacturingindustry.
A bioassay for possible carcinogenicity of technical-grade1-amino-2-methylanthraquinone was conducted using Fischer 344 rats andB6C3F1mice. 1-Amino-2-methylanthraquinonewas administered in the feed, at either of two concentrations, to groups of 45to 50 males and females of each species. The high and low time-weightedaverage concentrations of 1-amino-2-methylanthraquinonewere 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-weightedaverage concentrations were the same, 0.06 percent. For each species, 50animals of each sex were placed on test as controls. The period of compoundadministration was 78 weeks for rats followed by 26 to 28 additional weeks ofobservation, and 73 weeks for mice followed by 24 to 25 additional weeks ofobservation.
A statistically significant positive association between compoundadministration and mortality was established for the male and female dose Amice. Dose A mice did not survive sufficiently long to be at risk fromlate-developingtumors. Survival in all other groups was adequate.
The incidence of hepatocellular carcinomas was statistically significant amongdosed rats of both sexes. Kidney neoplasms (the combined incidence oftubular-celladenomas,tubular-celladenocarcinomas, and adenocarcinomas NOS) were significantly increasedamongdosed male rats.
Administration of the compound was associated with a significant increase inthe combined incidence of hepatocellular carcinomas and neoplastic livernodules in female mice. No other neoplasms occurred in statisticallysignificant positive incidences in male or female mice.1-Amino-2-methylanthraquinone demonstrated nephrotoxic properties inmice ofboth sexes.
Under the conditions of this bioassay, 1-amino-2-methylanthraquinone wascarcinogenic in Fischer 344 rats, inducing hepatocellular carcinomas in rats ofboth sexes, and kidney tumors in male rats. The compound was carcinogenicinfemale B6C3F1 mice, producing an increased combined incidence ofhepatocellularcarcinomas and neoplastic nodules.