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Home » Study Results & Research Projects » NTP Study Reports » All Long-Term Reports » Abstract for TR-147 - Mexacarbate
Chemical Formula: C12H18N2O2 | - | 3D Structure* | |
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Mexacarbate is one of a group of agricultural pesticides that scientists at the National Cancer Institute noted, in the late 1960's, had not been adequately tested for carcinogenicity. Mexacarbate has been used as an insecticide and as a molluscicide for the control of pests on lawns, turf, and flowers.
A bioassay of technical-grade mexacarbate for possible carcinogenicity was conducted using Osborne-Mendel rats and B6C3F1 mice. Mexacarbate was administered in the feed, at either of two concentrations, to groups of 50 male and 50 female animals of each species. The time-weighted average high and low dietary concentrations of mexacarbate were 418 and 209 ppm for male rats, 678 and 339 ppm for female rats, 654 and 327 ppm for male mice and 135 and 68 ppm for female mice. After a 78-week period of chemical administration, observation of rats continued for an additional 33 to 34 weeks and observation of mice continued for 14 to 15 additional weeks. For each species, 20 animals of each sex were placed on test as controls.
All groups except the male control mice survived sufficiently long to be at risk from late-appearing tumors. Because of poor survival of the male control mice, a pooled control group was used for statistical analysis of tumor incidence in male mice.
The possibility that female mice in this study did not receive maximum tolerated dosages of mexacarbate should be considered. Administration of mexacarbate had no significant effect on survival or body weights of female mice.
No neoplasms occurred in statistically significant increased incidences when dosed rats were compared to controls.
Among male mice surviving at least 56 weeks, significant associations with dietary concentrations were indicated by the Cochran-Armitage test for hepatocellular carcinomas, for subcutaneous fibrosarcomas and for fibromas of the skin. In none of these cases, however, were these results supported by significant Fisher exact tests.
Under the conditions of this bioassay, sufficient evidence was not obtained for the carcinogenicity of mexacarbate for Osborne-Mendel rats or B6C3F1 mice.
Male Rats: | Negative | |
Female Rats: | Negative | |
Male Mice: | Negative | |
Female Mice: | Negative |
Synonyms: 4-(dimethylamino)-3,5-dimethylphenyl methylcarbamate; 4-dimethylamino-3,5-xylyl methylcarbamate
Report Date: 1978
Target Organs from 2-year Studies
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Web page last updated on October 14, 2004
The National Institute of Environmental Health Sciences is one of the National Institutes of Health within the U.S. Department of Health and Human Services. The National Toxicology Program is headquartered on the NIEHS campus in Research Triangle Park, NC.