Although BPA is considered a toxic chemical in other countries such as Canada, the U.S. has been slow to address the issue, said vom Saal. Until now, most studies involving BPA have been conducted on laboratory mice and rats, leading U.S. regulatory agencies to call for studies in primates. With funding provided by the National Institute of Environmental Health Sciences (NIEHS), a research institute of the National Institutes of Health, vom Saal and his colleagues studied the chemical’s blood levels in pregnant female rhesus monkeys and their fetuses, which are considered to be very similar to human fetuses.
After collecting tissue samples, other researchers analyzed the tissues to determine if BPA exposure was harmful to fetal development. Researchers found evidence of significant adverse effects in mammary glands, ovaries, brain, uterus, lung and heart tissues in BPA exposed fetus when compared to fetuses not exposed to BPA. The abnormalities were caused by levels of BPA in the monkey fetuses that were very similar to levels reported in previous studies of BPA in human fetuses.
“The very low-level exposure to BPA we delivered once a day to the rhesus monkeys is far less than the BPA levels humans are exposed to each day, which reflects multiple exposures,” vom Saal said. “Our findings suggest that traditional toxicological studies likely underestimate actual human exposure and show, unequivocally, that biologically active BPA passes from the mother to the fetus. Additionally, our latest study shows that BPA causes damage to developing systems of monkey fetuses, and this is of great concern for human fetuses.”
The study, “Bisphenol A (BPA) pharmacokinetics with daily oral bolus or continuous exposure via silastic capsules in pregnant rhesus monkeys: relevance for human exposures,” was funded in part by the NIEHS and was published in Reproductive Toxicology in collaboration with Catherine A. VandeVoort with the Department of Obstetrics and Gynecology and the California National Primate Research Center at the University of California, Davis; Julia A. Taylor and Wade V. Welshons with the University of Missouri; Pierre-Louis Toutain with the Univesite de Toulouse; and Patricia A Hunt with the School of Molecular Biosciences at Washington State University.