1. National Institute of Diabetes and Digestive and Kidney Diseases (R.S.L., S.N., J.B., P.A.P., P.A.T.), National Institutes of Health, Department of Health and Human Services, Phoenix, Arizona 85016;
2. Endocrinology Unit, Department of Medical Sciences (D.J.W., D.E.W.L., B.R.W.), University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, United Kingdom