1. From the Departments of Biology (Q.W., J.L.-C.L., E.A.G.-W., J.J.-C.L.), Pediatrics (B.E.R., T.D.S.), and Obstetrics and Gynecology (B.Y.), University of Iowa, Iowa City; Department of Physiology (H.-Z.F., J.-P.J.), School of Medicine, Wayne State University, Detroit, Mich; and Institution of Physiology (F.-C.C., C.-I.L.), National Defense Medical Center, Taipei, Taiwan.