1. Department of Endocrinology & Metabolism, School of Medicine; Kyung Hee University; Seoul 02447 Republic of Korea
2. Department of Biomedical Laboratory Science, College of Health Sciences; Cheongju University; Cheongju Chungbuk 28503 Republic of Korea
3. Department of Medicine, Graduate School; Kyung Hee University; Seoul 02447 Republic of Korea
4. Department of Endocrinology & Metabolism; Kyung Hee University Hospital; Seoul 02447 Republic of Korea
5. Department of Physiology; Kyung Hee University; College of Medicine Seoul 02447 Republic of Korea