1. Laboratory Animal Science Division, Astellas Research Technologies Co., Ltd., 21 Miyukigaoka, Tsukuba-shi, Ibaraki 305-8585, Japan
2. United Graduate School of Agriculture Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
3. Screening Science and Technology Division, Astellas Research Technologies Co., Ltd., 21 Miyukigaoka, Tsukuba-shi, Ibaraki 305-8585, Japan
4. College of Agriculture, Ibaraki University, 3-21-1 Chuou, Ami-machi, Inashiki-gun, Ibaraki 300-0393, Japan