1. Center for Endocrinology (H.G.M., G.B.), Metabolism and Molecular Medicine, Department of Medicine, Northwestern University Medical School and Veterans Administration Chicago Health Care System, Lakeside Division, Chicago, Illinois 60611
2. Division of Endocrinology (R.B., J.N.), Catholic University, B3000 Leuven, Belgium; and State Research Center, Institute for Biomedical Problems, Russian Academy of Sciences, 123007 Moscow, Russia