1. First Department of Internal Medicine (S.Y., I.M., K.Z., S.E.), School of Medicine, University of Occupational and Environmental Health, 1–1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807, Japan
2. Physiology (Y.U., H.Y.), School of Medicine, University of Occupational and Environmental Health, 1–1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807, Japan
3. Department of Physiology (H.K.), Miyazaki Medical College, 5200 Kihara Kiyotake Miyazaki-gun, Miyazaki, 889–16, Japan