What is Insulin?
What is Insulin?
By Dr Ananya Mandal, MD
Insulin is a hormone that is important for metabolism and utilization of energy from the ingested nutrients - especially glucose.
Insulin chemistry and etymology
Insulin is a protein chain or peptide hormone. There are 51 amino acids in an insulin molecule. It has a molecular weight of 5808 Da.
Insulin is produced in the islets of Langerhans in the pancreas. The name insulin comes from the Latin ''insula'' for "island" from the cells that produce the hormone in the pancreas.
Insulin's structure varies slightly between species of animal. Both porcine (from pigs) and bovine (from cows) insulin are similar to human insulin but porcine insulin resembles human insulin more closely.
What does insulin do?
Insulin has several broad actions including:
It causes the cells in the liver, muscle, and fat tissue to take up glucose from blood and convert it to glycogen that can be stored in the liver and muscles
Insulin also prevents the utilization of fat as an energy source. In absence of insulin or in conditions where insulin is low glucose is not taken up by body cells, and the body begins to use fat as an energy source
Insulin also controls other body systems and regulates the amino acid uptake by body cells
It has several other anabolic effects throughout the body as well
Secretion of insulin