1. Departments of Endocrinology and Metabolism (P.H.B., A.M.P.A., H.P.S.), University of Amsterdam, 1100 DE Amsterdam
2. linical Chemistry (M.T.A., E.E.), University of Amsterdam, 1100 DE Amsterdam
3. Departments of Internal Medicine (H.P.), 2300 RC Leiden, The Netherlands
4. Center for Liver, Digestive, and Metabolic Diseases, Academic Hospital Groningen (F.K.), 9713 GZ Groningen
5. Biochemistry (A.J.M.), Academic Medical Center, University of Amsterdam, 1100 DE Amsterdam
6. Endocrinology (P.H.B., J.A.R.), Leiden University Medical Center, 2300 RC Leiden, The Netherlands