What is Adiponectin?
Adiponectin is a 244-amino-acid peptide hormone secreted exclusively by adipocytes, circulating in several oligomeric forms — trimeric (low molecular weight), hexameric (medium), and a high-molecular-weight (HMW) multimer that is thought to be the most metabolically active. Unlike most adipokines, adiponectin secretion is inversely related to adipose tissue mass, so concentrations fall in obesity and insulin resistance. It acts through two G-protein-coupled receptors, AdipoR1 in skeletal muscle and AdipoR2 in the liver, to activate AMP-activated protein kinase and peroxisome proliferator-activated receptor alpha pathways, enhancing fatty-acid oxidation, glucose uptake, and insulin sensitivity while suppressing hepatic gluconeogenesis and inflammation.