Adiponectin as an adipokine

Adiponectin, a major insulin-sensitizing, multimeric hormone, is secreted by adipocytes and circulates at high levels in plasma. In the peripheral tissues, adiponectin activates AMPK and PPAR- to enhance glucose uptake and fatty acid oxidation in muscle, in liver, adiponectin synergizes with insulin to suppress hepatic glucose output. Adiponectin also acts in the central nervous system. By activating AMPK in the hypothalamic neurons, adiponectin increases food intake and decreases peripheral energy expenditure. This protein binds to three known receptors-AdipoR1, AdipoR2 and T-cadherin-but the way in which these receptors are coupled to downstream signaling is poorly understood. Along with metabolic functions, adiponectin also has anti-inflammatory and anti-atherogenic properties, making it a truly multi-functional adipokine.