1. From the Departments of Internal Medicine (S.D., C.D.S., F.M.F., S.R.L.), Physiology and Biophysics (C.D.S.), and Pharmacology (F.M.F.), University of Iowa Carver College of Medicine, Iowa City, Iowa; Baylor Institute of Metabolic Disease (E.A., T.B.), Dallas, Texas; the Institute of Experimental and Clinical Pharmacology and Toxicology (R.H.B.), University Hospital Hamburg-Eppendorf, Hamburg, Germany; and the Veterans Affairs Medical Center (S.R.L.), Iowa City, Iowa.