1. Department of Diabetes, Endocrinology and Metabolism, Division of Internal Medicine, Shinshu University School of Medicine, Matsumoto 390-8621, Japan
2. Department of Diabetes, Endocrinology and Metabolism, Shinonoi General Hospital, Nagano 388-8004, Japan
3. Department of Drug Discovery Science, Shinshu University School of Medicine, Matsumoto 390-8621, Japan