[Insulin resistance and beta 3-adrenergic receptor function]

Beta 3-adrenergic receptors are expressed predominantly on white and brown adipocytes. Activation of the receptor stimulates lipolysis in adipose tissues and increases energy expenditure by thermogenesis in brown adipocytes. It is proposed that dysfunction of beta 3-adrenergic receptor result to obesity and insulin resistance. Trp64Arg mutation of human beta 3-adrenergic receptor gene is found frequently in Pima Indians and Japanese, and rare in Caucasians. Although the mutation have little, if any, functional disturbance especially in acute phase in vivo, it is reported to associate to obesity and earlier onset of type 2 diabetes. The role of beta 3-adrenergic receptor in insulin resistance is still unknown in detail. Further studies and clinical applications are expected.