1. From the Department of Biochemistry and Molecular Biology (A.H.S., R.A.I., W.Z., W.W., R.E.K., Y.X.) and Department of Obstetrics, Gynecology, and Reproductive Sciences (S.C.B.), The University of Texas Medical School at Houston, Houston, TX. Current address: Athar H. Siddiqui, Department of Pharmacology, Aligarh Muslum University, Uttar Pradesh, India.