Comparison of endocrine-mediated effects of two bisphenol A related compounds, 2,2-bis(4-cyanatophyenyl)propane and 4,4'-cyclohexylidenebisphenol, based on subacute oral toxicity studies using rats.

The purpose of this study was to compare endocrine-mediated effects of bisphenol A related compounds, 2,2-bis(4-cyanatophyenyl)propane and 4,4'-cyclohexylidenebisphenol with reference to OECD Test Guideline No. 407. Rats were orally gavaged with 0, 4, 20, and 100 mg/kg/day of 2,2-bis(4-cyanatophyenyl)propane, and 0, 30, 100, and 300 mg/kg/day of 4,4'-cyclohexylidenebisphenol for at least 28 days beginning at 8 weeks of age. Endocrine-mediated effects were not observed in rats given 2,2-bis(4-cyanatophyenyl)propane. Male accessory sex organ weights decreased in the 4,4'-cyclohexylidenebisphenol 300 mg/kg group and serum T4 values increased in all male groups treated with this compound. Our results suggest that endocrine-mediated changes caused by the present bisphenol related compound can be divided into estrogenic or thyroid hormonal effects, and estrogenic effects observed in the repeated-dose study were related to their estrogenic potency confirmed by uterotrophic assay.