1. Departments of Obstetrics, Gynecology, Reproductive Sciences and Physiology (G.W.A., T.W.B., E.D.A.), Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, Maryland 21201
2. Regeneron Pharmaceuticals, Inc. (S.J.W.), Tarrytown, New York 10591
3. Department of Physiological Sciences (G.J.P.), Eastern Virginia Medical School, Norfolk, Virginia 23507