1. Receptor Biology Section (J.F.C., J.L., K.S.K.), Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
2. Laboratory of Reproductive Biology (D.O.B.), Department of Cell Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
3. Departments of Obstetrics and Gynecology and Cell Biology (D.W.S.), Duke University Medical Center, Durham, North Carolina 27710