Ghasemi, Asghar, Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran, No. 24, Sahid-Erabi St, Yemen St, Chamran Exp, Tehran, Iran. P.O.Box: 19395-4763, Phone: +98 (21) 224 32 500, Fax: +98 (21) 224 16 264, 224 02 463, E-mail address: Ghasemi@endocrine.ac.ir, Iran, Islamic Republic of