Adiponectin is a hormone of adipose tissue, activating lipid metabolism and other physiological functions. Adiponectin deficiency induces obesity and decreases insulin-regulated carbohydrate metabolism, thus leading to insulin resistance. Blood level of adiponectin falls in type 2 diabetes. Adiponectin receptors--AdipoR1 and AdipoR2--are proteins with 7 transmembrane domains, which are synthesized mostly in muscles and the liver and function in a close connection with G proteins. Obesity and diabetes lower the tissue concentration of the receptors, thus impeding adiponectin regulation of lipid exchange and lowering the effectiveness of the insulin control of carbohydrate exchange. Adiponectin also influences cardiovascular functions and prevents atherosclerosis and some of the other kinds of vascular pathology.