1. Wallenberg and Lundberg Laboratories (E.B., E.O., B.M., B.S., M.L.X.F., F.W.), Department of Internal Medicine, Sahlgrenska University Hospital, 413 45 Goteborg, Sweden;
2. Department of Physiology (M.B., J.T.), Goteborg University, Medicinaregatan 7B, 413 90, Goteborg, Sweden;
3. Department of Clinical Physiology (V.K.), Sahlgrenska University Hospital, 413 45 Goteborg, Sweden;
4. Research Center for Endocrinology and Metabolism (O.I., G.M., J.I.), Department of Internal Medicine, Sahlgrenska University Hospital, 413 45 Goteborg, Sweden;
5. Max-Delbrück-Centrum fur Molekulare Medizin (W.S.), MDC, Robert-Rossle-Strasse 10, Berlin, D-13125, Germany