1. Department of Endocrinology, Metabolism and Nephrology, Kochi Medical School , Kochi, University , Kohasu, Oko-cho, Nankoku, Kochi 783-8505 , Japan
2. Laboratory of Anatomy , Department of Biomedical Sciences, Graduate School of Veterinary Medicine , Hokkaido University , Kita 18, Nishi 9, Kita-Ku, Sapporo , 060-0818 , Japan