PROVIDENCE, R.I. [Brown University] Female mouse fetuses exposed to very high doses of a common industrial chemical that makes plastics more pliable develop significant reproductive alterations and precancerous lesions as they grow up, according to a new toxicology study conducted at Brown University.
The administered doses of MEHP, the chemical that results when animals metabolize the industrial phthalate DEHP, were much higher than any normal environmental exposure that people or animals would encounter, said Mary Hixon, assistant professor of pathology and laboratory medicine (research) in The Warren Alpert Medical School of Brown University and a study co-author.
"For these doses, you'd have to be eating the plastic or drinking the plastic," she said. "The real risk is probably minimal for most people."
But when toxicologists set out to determine the effect of a chemical on an organism, they often start with atypically high doses and work their way down to the levels where any adverse effects disappear. Until now, no one had done such a study on the effects of exposure to doses of MEHP in adult mice while they were still in utero.
The new study published in advance online March 5 in the journal Reproductive Toxicology, therefore provides new basic insights into how the controversial chemicals could affect developing female reproductive systems. Because prior studies have associated certain phthalates with several health effects in humans, especially with male reproductive systems, the U.S. Environmental Protection Agency has said it will add eight phthalates to its "Concern List."
High doses, significant effects
To conduct the study, Hixon and graduate student Benjamin Moyer fed either pure corn oil or corn oil laced with three different concentrations of MEHP (100, 500 and 1,000 milligrams per kilogram of body weight) to pregnant mice in days 17 to 19 of their term. Then they looked f
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