1. Department of Endocrinology and Reproduction (A.L.L.D., M.J.G.G., P.K., J.Th.J.U., J.A.G., A.P.N.T.), Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, 3000 DR Rotterdam, The Netherlands
2. Department of Physiology (H.A.I.), Center for Reproductive Sciences, University of California-San Francisco, California 94143-0444
3. Department of Pharmacology (M.W.N.), Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada B3H 2Y9