ABSTRACT
Increased adipose mass, which is associated with insulin resistance and type 2 diabetes mellitus (T2DM) (Kahn and Flier 2000), is characterized by the impaired ability of insulin to reduce glucose output in the liver and to augment glucose uptake in adipose and muscle tissues (Saltiel and Khan 2001). The excess energy stored in adipose tissue plays a major role in the maintenance of whole-body energy homeostasis. It is well established that adipose tissues not only serve as inert energy storage depots but also secrete a number of signaling factors into the circulation, such as C-reactive protein, leptin, resistin, adiponectin, tumor necrosis factor-α (TNFα), and others (Rajala and Scherer 2003). These factors are believed to be involved in the development of insulin resistance. Another such signaling factor, retinol-binding protein-4 (RBP4), a protein whose only function was thought
2.1 Introduction .................................................................................................... 31 2.2 Serum RBP4 and Retinoid Metabolism .......................................................... 32
2.2.1 Vitamin A and Adipogenesis .............................................................. 33 2.3 Obesity, Insulin Resistance, and T2DM ......................................................... 33 2.4 Association between RBP4, Obesity, and Insulin Resistance ........................34
