1. Laboratory of Animal Physiology (Y.Y., M.I., A.O., M.Sa.), Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara 727-0023, Japan;
2. Laboratory of Theriogenology (M.O., Y.G., R.N., M.H.), School of Veterinary Medicine, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan;
3. United Graduate School of Veterinary Medicine (Y.G.), Yamaguchi University, Yamaguchi 735-8515, Japan;
4. Laboratory of Reproductive Endocrinology (M.Sh.), Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima 739-8528, Japan