1 Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
2 German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
3 Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, 72076 Tübingen, Germany.
4 Department of Medicine-Endocrinology and Diabetes and Metabolism, Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35899, USA.