A pollutant that can alter growth.

Fetuses are particularly vulnerable to the effects of hormones. To tease out the potential consequences of prenatal exposure to bisphenol A (BPA), Frederick S. vom Saal and his colleagues at the University of Missouri in Columbia fed pregnant mice on days 11 to 17 of gestation with food containing BPA at concentrations equivalent to 2 parts per billion of the rodents' body weight. The dose was meant to represent an amount that people could be exposed to from all sources, including dental sealants (SN: 4/6/96, p. 214) and foods in plastic-lined cans (SN: 6/3/95, p. 341). At birth, all of the offspring were transferred for nursing to foster moms--females that had not been treated with the estrogen-mimicking pollutant.

The brief, early exposure had lasting effects. Compared to mice from untreated mothers, offspring exposed to BPA were 10.6 percent bigger at weaning and entered puberty 2 days earlier. Vom Saal's group presented portions of the study in July at a federally sponsored Estrogens in the Environment conference in Arlington, Va.

In a related study, vom Saal's team now finds that comparable exposure to BPA during the same period of gestation alters slightly the development of testes and accessory male reproductive organs in mice.

"The jury's still out on what this means for humans," vom Saal says. However, he notes, there have been reports that high concentrations of other estrogen-mimicking pollutants alter children's stature, behavior, and intellectual development (SN: 11/11/95, p. 310).