Insulin is a polypeptide hormone with molecular weight of 6,000 Daltons, composed of two peptides chains, A and B, jointed by two cross-linked disulphide bonds and synthesised by the beta cells of the islets of Langherans of the pancreas. Insulin influences most of the metabolic functions of the body. Its best known action is to lower the blood glucose concentration by increasing the rate at which glucose is converted to glycogen in the liver and muscles and to fat in adipose tissue, by stimulating the rate of glucose metabolism and by depressing gluconeogenesis. Focus on hemolysis: Hemolysis interferes with the assay by degrading insulin. To prevent hemolysis consequences, an inhibitor cocktail (Item No. 18429) and a procedure are available.