1. Division of Endocrinology and Metabolism, Department of Internal Medicine, Dongguk University Ilsan Hospital, Goyang-shi, Gyeonggi-do 410-773, Korea
2. Institute of Endocrine Research, Yonsei University College of Medicine, Seoul 120-752, Korea
3. Department of Medicine, Graduate School, Dongguk University, Seoul 100-715, Korea
4. Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Seoul 130-702, Korea
5. Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul 120-752, Korea
6. Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul 120-752, Korea