1. Division of Hypertension, University Hospital, CH-1011 Lausanne, Switzerland, Department of Pharmacy, Swiss Federal Institute of TechnologyZurich, Winterthuerstrasse 190, CH-8057 Zurich, Switzerland, Institut de Biologie Animale, Université de Lausanne, Batiment de Biologie, CH-1015 Lausanne, Switzerland, and Biochemical Research, Boehringer Ingelheim KG, D-55127 Ingelheim, Germany