indication

For treatment of Type I and II diabetes mellitus.

pharmacology

Used in the treatment of type I and type II diabetes, 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.

mechanism of action

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. These activated proteins, in turn, lead to the activation of downstream signaling molecules including PI3 kinase and Akt. Akt regulates the activity of glucose transporter 4 (GLUT4) and protein kinase C (PKC) which play a critical role in metabolism and catabolism.

biotransformation

Insulin is predominantly cleared by metabolic degradation via a receptor-mediated process.