1. Third Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Yamaguchi 755-8505;
2. Division of Molecular Metabolism and Diabetes, Department of Internal Medicine, Tohoku University Graduate School of Medicine, Sendai 980-8574;
3. Faculty of Medicine, Department of Internal Medicine, University of Tokyo, Tokyo 113-8566; and
4. Department of Molecular Biology, Yokohama City University School of Medicine 3 – 9, Yokohama 236, Japan