1. Research Department, Laboratory of Racing Chemistry, 4-37-6 Kamiyoga, Setagaya-ku, Tokyo 158-0098, Japan
2. Equine Research Institute, Japan Racing Association, 321-4 Tokami-cho, Utsunomiya, Tochigi 320-0856, Japan
3. Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-0054, Japan