Charting Hormonal Effects of Chemicals in Plastic

Plastic is an integral part of the American consumer culture, but Dr. Heather Patisaul worries that its pervasive presence also poses risks. An assistant professor in the Department of Biology, Patisaul is studying the possible health implications of long-term exposure to bisphenol A. Commonly known as BPA, the organic compound makes plastic hard and clear. About 6 billion pounds of it are produced each year to be included in items from beverage containers to eyeglass frames to epoxy linings inside cans and jars.

BPA was initially used in the 1930s as a synthetic estrogen. Patisaul says previous research has shown that the compound can interfere with animals’ endocrine systems. That is especially critical during early development, when hormones help males and females develop gender-specific traits. Patisaul, who has studied the endocrine-disruptive properties of soy products, received two Recovery Act-funded grants totaling $174,000 to examine the changes that occur in the brains of rats exposed to BPA. “If we’re going to understand the threat to human health,” she says, “we need to understand what’s happening in animals.”

As part of a two-year grant with the Food and Drug Administration, Patisaul received tissue samples from the FDA, which is studying BPA’s effects on reproduction. Rats are given various doses of BPA from before birth until adulthood to mimic what Patisaul calls the “consistent and constant” exposure humans receive. The FDA is collecting data on the animals’ growth and development to build a risk assessment for humans. Patisaul hired recent NC State graduates to prepare samples of brains from rats in the FDA study so her research team could examine the gene expression of estrogen receptors during early development. By using radioactive tags that identify various receptors, the team has detected changes in the hypothalamus, which controls basic bodily functions as well as emotion and behavior, in rats exposed to BPA.

Patisaul used a two-year grant through the National Institute of Environmental Health Sciences to hire a technician to help analyze tissue samples from rats in a University of Rochester study. Researchers in New York are exposing the animals to BPA before and shortly after birth to study the way they move and play as they develop. Patisaul says male and female rats have distinctly different patterns of locomotion and play, and the study is designed to determine whether BPA affects those behaviors. “We really need more extensive testing of chemicals like this in consumer products so we can make them safer,” Patisaul says.

 

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Two Recovery Act Grants allowed Dr. Heather Patisaul to study the effects of Bisphenol A, found in many household products.