Research targets chemical in plastics

By Blythe Bernhard
ST. LOUIS POST-DISPATCH
07/16/2009

A chemical commonly used in plastics causes damage to reproductive systems in mice, according to new research from the University of Illinois at Urbana-Champaign.

Bisphenol A, found in some baby bottles, compact discs, plastic utensils and food containers, has already been proved to cause reproductive issues in the babies of mice that were exposed to the chemical in pregnancy. Now researchers have shown the chemical reduces the production of hormones in adult mice.

The study, led by veterinary biosciences professor Jodi Flaws, is believed to be the first to show that Bisphenol A (BPA) exposure can harm adult reproductive cells. Researchers are scheduled to present their findings next week in Pittsburgh at the Society for the Study of Reproduction's annual meeting.

More studies are needed to determine if the same negative effects would be seen in humans, researchers said.

Some plastics manufacturers have already started removing the chemical following earlier research that raised concerns about BPA levels found in human urine, blood and breast milk.

In one sample from 2004, the federal Centers for Disease Control and Prevention found BPA in the urine of 93 percent of the 2,517 Americans who were tested. Women generally had higher BPA levels than men, the testing showed.

The structure of BPA is similar to the steroid hormone called estradiol. The BPA, like estradiol, can attach to estrogen receptors on cells. The BPA may then block or stimulate the effects of estrogen.

In the study on mice, researchers found that the chemical harms the cells, follicles and hormones necessary for ovulation.

"These are the only follicles that are capable of ovulating and so if they don't grow properly, they're not going to ovulate and there could be fertility issues," Flaws said in a statement.

The hormones are not only required for reproduction, but also contribute to bone and heart health.

Researchers found that BPA affected follicle growth in the mice in two days following an exposure. About a week after a heavy exposure, the levels of the hormones progesterone, testosterone and estradiol were lowered by nearly 100 percent.

Federal health officials have said humans are not exposed to the high levels of BPA that have been shown to be harmful in animals. But the 2008 report from the U.S. Department of Health and Human Services also said the previous research does cause concern for exposure to fetuses, infants and children.

The Illinois scientists said their research suggests possible problems for adults, including infertility issues.