1. Animal Reproduction and Biotechnology Laboratory (D.L.D., T.M.N., C.M.C.), Department of Physiology, Colorado State University, Fort Collins, Colorado 80523
2. Department of Pharmacology (C.C.Q.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
3. USDA-CSREES-NRI (D.L.H.), Washington, DC 200250–2241