Bioassay of anthranilic acid for possible carcinogenicity.
A bioassay of anthranilic acid for possible carcinogenicity was conducted by administering the test chemical in feed to Fischer 344 rats and B6C3F1 mice. Groups of 35 rats and 35 mice of each sex were administered anthranilic acid at one of the following doses, either 15,000 or 30,000 ppm for the rats, and either 25,000 or 50,000 ppm for the mice, 5 days per week for 78 weeks, then observed for an additional 26-27 weeks. Matched controls consisted of groups of 15 rats and 15 mice of each sex; pooled controls, used for statistical evaluation, consisted of the matched controls combined with 15 untreated male and 15 untreated female animals of each species from a similar bioassay of another test chemical Except for the matched-control male mice, all surviving animals in the study were killed at 104-106 weeks. Half of the matched-control male mice, which were accidentally killed at week 12, were excluded from the report; the remaining matched-control males died by week 94. Mean body weights of the low-and high-dose male and high-dose female rats were lower than those of the corresponding matched controls for the duration of the study. The weights of the low-dose females were similar to those of the matched controls for the first 45 weeks, after which they declined slightly. The weights of the low-dose male mice were similar to those of the matched controls, while those of the high-dose males and of the low-and high-dose females were slightly lower. Survival of both treated and matched-control groups of rats of both sexes was high; survival of treated mice of both sexes and of female matched controls, although lower than that of the rats, was sufficient for meaningful statistical analyses of the incidences of tumors. In rats, a variety of neoplasms were observed in both treated and control animals. Few malignant tumors were found, and no tumors occurred in treated animals in statistically significant incidences when compared with control animals. In mice, a variety of neoplasms were observed in both treated and control animals. These neoplasms are not uncommon in this strain of mouse, and none occurred in treated animals in statistically significant incidences when compared with control animals. It is concluded that under the conditions of this bioassay, anthranilic acid was not carcinogenic for either Fischer 344 rats or B6C3F1 mice.