Assessment of Polystyrene Extract for Estrogenic Activity in the Rat Uterotrophic Model and an in Vitro Recombinant Receptor Reporter Gene Assay

The purpose of the study was to determine whether polystyrene used in food-contact applications would elicit an estrogenic response when extracts simulating exaggerated conditions of use were subjected to in vivo and in vitro tests. A sample of polystyrene was subjected to extraction conditions that simulate, or exaggerate, the actual food-contact uses of polystyrene to maximize the amount of low molecular weight polystyrene extractables. the food-simulating solvent and the time and temperature conditions recommended by the Food and Drug Administration (FDA) were selected to maximize the level of extractable components from polystyrene. the extract was examined for its estrogenic response in vivo using the immature rat uterotrophic assay and in vitro using an estrogen receptor (ER)-mediated recombinant receptor reporter gene assay. in vivo, the uterine weights of juvenile female Sprague Dawley® rats (10 rats/group) were determined after oral gavage exposure to the extract (two dosage levels: one represent...