Adiponectin, an adipokine secreted by adipocytes, is believed to play important roles in various metabolic processes, includ- ing glucose regulation and fatty acid catabolism [The role of the novel adipocyte-derived hormone adiponectin in human disease. Eur. J. Endocrinol., 2003;148, 293– 300]. Plasma adiponectin level is negatively correlated with body mass index (BMI), glucose, insulin and triglyceride levels and is positively associated with high-density lipoprotein cholesterol (HDL-C) concentration and insulin-stimulated glucose disposal [The role of the novel adipocyte-derived hormone adiponectin in human disease. Eur. J. Endocrinol., 2003;148, 293– 300].