1. Institute of Experimental Pediatric Endocrinology (G.K., A.G., H.K., H.B.), Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
2. National Institutes of Health (S.N.), Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892