Global citimpact: 6.79 Researcher at Internal Medicine (Dept. of Endocrinology, Metabolism, Nephrology and Clinical Chemistry), University of Tuebingen, Otfried-Muellerstrasse 10, 72076 Tuebingen, ; Center for Medical Research, Medical University Graz, Stiftingtalstr. 24, 8010 Graz, . Electronic address: .