From the Division of Endocrinology, Diabetes, and Hypertension, University of Southern California School of Medicine, Los Angeles (Dr Singer); the Divisions of Endocrinology, The Johns Hopkins University School of Medicine (Drs Cooper and Ladenson) and Mount Sinai Hospital (Dr Cooper), Baltimore, Md; the Thyroid Unit, Massachusetts General Hospital, Boston (Dr Daniels); the Division of Endocrinology, University of California, San Francisco, School of Medicine (Dr Greenspan); the Division of Endocrinology, University of Miami School of Medicine, Miami, Fla (Dr Levy); the Division of Endocrinology, University of Massachusetts Medical School, Worchester (Dr Braverman); the Department of Surgery, Mt Zion Medical Center, University of California, San Francisco, School of Medicine (Dr Clark); the Division of Nuclear Medicine, Stanford University School of Medicine, Stanford, Calif (Dr McDougall); the Division of Endocrinology, University of Kentucky, Lexington (Dr Ain); and Endocrine Associates of Dallas, Dallas, Tex (Dr Dorfman).
Accepted for publication June 3, 1996.

The authors gratefully acknowledge the secretarial assistance of Elsa C. Ahumada. Reprints: Peter A. Singer, MD, 1335 San Pablo St, Room 120, Los Angeles, CA 90033.