[1] Med Univ Graz, Dept Internal Med, Div Endocrinol & Metab, Graz, Austria
[2] Univ Cambridge, Welcome Trust MRC Inst Metab Sci, Cambridge, England
[3] Univ Sheffield, Acad Unit Diabet Endocrinol & Metab, Dept Human Metab, Sheffield, S Yorkshire, England
[4] Kings Coll London, Diabet Res Grp, London WC2R 2LS, England
[5] Profil Inst Stoffwechselforsch, Neuss, Germany