The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings may not have been peer reviewed and were not evaluated in accordance with the levels of evidence criteria established by NTP in March 2009. For more information, see the Explanation of Levels of Evidence for Developmental Toxicity. The findings and conclusions for this study should not be construed to represent the views of NTP or the U.S. Government.
Bisphenol A, a widely distributed industrial chemical used in making epoxy resins and polycarbonates, was evaluated for toxic and teratogenic effects in timed-pregnant Sprague Dawley CD rats (n=27-29). BPA (0, 160, 320, 640 and 1280 mg/kg/day) suspended in corn oil was given by gavage (5.0 mL/kg body weight) daily on gestational days 6 through 15. Females were weighed and observed daily. At sacrifice a total of 18-29 confirmed-pregnant females per treatment group were evaluated. The gravid uterus of each dam was weighed, and the number of implantation sites and live, dead, or resorbed fetuses were recorded. All live fetuses were weighed and examined for external, visceral, and skeletal malformations. Dams exhibited clinical signs of toxicity including piloerection, weight loss, lethargy, pica, rough coat, wet urogenital area, and alopecia. These were seen in all dose groups, and with greater frequency at higher doses.
Maternal mortality was 0% for all but the 1280 mg/kg/day dose group, which was 26%. Due to this high mortality, data from the 1280 mg/kg/day group will not be further considered in this summary.
Maternal body weight on gd 0 and gd 6 did not differ among the remaining dose groups. But at gd 11 and 15, maternal body weight was lowered for all BPA treatment groups. Gravid uterine weight, absolute maternal liver weight, and relative maternal liver weight were unaffected by treatment. BPA produced NO significant fetal effects at doses ¾ 640 mg/kg.
In conclusion, BPA in rats was not a developmental toxicant at doses that were maternally toxic. The developmental no observed adverse effect level was 640 mg/kg. A maternal NOAEL was not established, based on effects on maternal body weight; the lowest observed adverse effect level for maternal body weight effect in this study was 160 mg/kg.