Development and Preliminary Validation of a Rapid Progestin-Based Endocrine Disruption Screening Assay

Concerns regarding the presence of endocrine disruptors in food, water, or other environmental media as well as concerns about the potential risk they pose to humans and wildlife have been growing in recent years. Passage in 1996 of the Food Quality Protection Act and Amendments to the Safe Drinking Water Act reflected these concerns and required the U.S. Environmental Protection Agency to develop a screening program, using appropriate validated test systems and other scientifically relevant information, to determine whether certain substances may have an endocrine effect in wildlife and humans. The proposed work will result in the validation of an assay that tests substances that might disturb reproductive and developmental processes in animals by interfering with the endocrine system. The primary goal of the proposed research is to validate and commercialize the Xenopus laevis oocyte maturation germinal vesicle breakdown (GVBD) model as a system for the rapid evaluation of endocrine-disrupting chemicals (EDCs) found in the workplace or the environment. Specifically, Fort Environmental Laboratories, Inc., will validate and standardize a 24-hour X. laevis assay designed to evaluate progestin-active or antiprogestin EDCs in vitro by conducting an interlaboratory validation study with a series of known mammalian EDCs, compounds found to be inactive, and chemicals with unknown activity. Because none of the currently developed EDC screening systems are capable of specifically screening for progesterone-active EDCs, the successful completion of the in vitro oocyte GVBD model development will provide the scientific community with a nonmammalian, cost-effective, rapid, and reliable method of prescreening EDCs. The ability to rapidly and cost effectively screen for and evaluate the mechanisms of EDCs is an attractive alternative to the current laborious and expensive testing systems used today. Increasing concern over the widespread finding of EDCs in the environment has dramatically increased the need for standardized assays, such as the X. laevis GVBD model, because few other progestin/antiprogestin-based in vitro assays are available today.