Adiponectin is a protein hormone secreted mainly by fat cells, encoded by the ADIPOQ gene and containing 244 amino acids. Adiponectin levels in adults are negatively correlated with fat storage.Adiponectin can bind to several receptors, and the two receptors share homology with G protein-coupled receptors, one belonging to the cadherin family.These have distinct tissue specificities within the body and have different affinities to the various forms of adiponectin. The receptors affect the downstream target AMP kinase, an important cellular metabolic rate control point. Expression of the receptors is correlated with insulin levels, as well as reduced in mouse models of diabetes, particularly in skeletal muscle and adipose tissue.