Triphenyltin hydroxide, an organometallic compound used as a fungicide and antifeeding compound for insect control, was selected for bioassay by the National Cancer Institute because of its use on edible crops and a lack of adequate chronic toxicity data.
A bioassay of triphenyltin hydroxide for possible carcinogenicity was conducted using Fischer 344 rats and B6C3F1 mice. Triphenyltin hydroxide was administered in the feed, at either of two concentrations, to groups of 50 male and 50 female animals of each species. The high and low concentrations of triphenyltin hydroxide were, respectively, 75 and 37.5 ppm for rats and mice. After a 78-week period of compound administration, there was an additional observation period of 26 weeks for both species. Twenty animals of each sex and species were placed on test as controls.
For male mice, there was a significant positive association between dosage and mortality. In both species, however, adequate numbers of animals survived sufficiently long to be at risk from late-developing tumors. Except for a slight depression of mean body weight gain in male rats and female mice, compound-related mean body weight depression was not observed in either species. In female rats no significant accelerated mortality, retardation of growth, or other signs of toxicity were associated with the dietary administration of triphenyltin hydroxide. Therefore, it is possible that the compound was not administered at the maximum tolerated concentrations.
No tumors occurred at a significantly higher incidence in dosed rats or mice than in controls.
Under the conditions of this bioassay, there was no evidence for the carcinogenicity of triphenyltin hydroxide to Fischer 344 rats or B6C3F1 mice.