1. From the Department of Cardiology and Angiology (C.K., J.S., J.W., M.L., H.D., B. Schieffer), Medizinische Hochschule Hannover; the Department of Chemistry (B. Schmidt), University Hannover; Lower-Saxony Institute of Peptide Research (M.W., W.-G.F.), Hannover, Germany; and the Clinical Pharmacology Unit (R.H.B.), Department of Pharmacology, University Hospital Hamburg, Germany.