Indication Indicated as an adjunct to diet and exercise to improve glycemic control in adults and children with type 1 and type 2 diabetes mellitus. Mechanism of action The primary activity of insulin is the regulation of glucose metabolism. Insulin promotes glucose and amino acid uptake into muscle and adipose tissues, and other tissues except brain and liver. It also has an anabolic role in stimulating glycogen, fatty acid, and protein synthesis. Insulin inhibits gluconeogenesis in the liver. Insulin binds to the insulin receptor (IR), a heterotetrameric protein consisting of two extracellular alpha units and two transmembrane beta units. The binding of insulin to the alpha subunit of IR stimulates the tyrosine kinase activity intrinsic to the beta subunit of the receptor. The bound receptor is able to autophosphorylate and phosphorylate numerous intracellular substrates such as insulin receptor substrates (IRS) proteins, Cbl, APS, Shc and Gab 1