Biograghical note of the first author: Qi-Chen FANG, female, born in 1964, M. D., majoring in cell biology. Correspondence should be addressed to: Wei-Ping JIA, M. D., Ph.D., Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiaotong University, 600 Yishan Road, Shanghai 200233, China. Tel: 86-21-64369181-8922. Fax: 86-21-64368031. E-mail: wpjia@sjtu.edu.cn