1. Department of Physiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
2. Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
3. Department of Internal Medicine, The Catholic University of Korea, Seoul St. Mary’s Hospital, Seoul 06591, Korea
4. Department of Physiology, Jeonbuk National University Medical School, Jeonju 54907, Korea