1 Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tuebingen, Tuebingen, Germany.
2 Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tuebingen, Tuebingen, Germany; Institute of Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen, Tübingen, Germany; German Center for Diabetes Research at the University Tübingen, Tübingen, Germany.
3 Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
4 Division of Endocrinology, Diabetology and Nephrology, Department of Internal Medicine, University Hospital Tuebingen, Tuebingen, Germany; Institute of Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen, Tübingen, Germany; German Center for Diabetes Research at the University Tübingen, Tübingen, Germany. Electronic address: ferruh.artunc@med.uni-tuebingen.de.