Adiponectin is a hormone that is derived from adipose tissue and is reduced in obesity-linked diseases including insulin resistance/type 2 diabetes and atherosclerosis.
Adiponectin binds to two distinct adiponectin receptors (AdipoR1 and AdipoR2) identified and exerts its anti-diabetic effects through activation of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor (PPAR)α pathways in liver and skeletal muscles as well as amelioration of vascular dysfunction through activation of endothelial nitric oxide (NO) production and anti-atherogenic effects through inhibition of inflammation in the various vasculature. In liver AdipoR1 involved in activating AMP-activated kinase (AMPK), while AdipoR2 is involved in activation of PPARa, leading to increased insulin sensitivity.
The skeletal muscle and liver, which are the principal storage for glucose and fatty acids, are responsible for energy homeostasis. The beneficial effect of adiponectin in insulin-sensitive organs including skeletal muscle and liver appears to be mediated by an increase in glucose utilization and fatty-acid oxidation via activation of AMPK and PPARα. In addition, adiponectin played a protective role in the pathogenesis of vascular diseases by promoting NO production as well as inhibiting inflammation and oxidative stress.