Regulation of Insulin Secretion and Islet Cell Function

Abstract

The $β$ cells of the islets of Langerhans are the only cells in the body that produce a ­meaningful quantity of insulin, a hormone that has evolved to be essential for life, exerting critical control over carbohydrate, fat, and protein metabolism. Islets are scattered throughout the pancreas; although they vary in size, they typically contain about 1,000 cells, of which approximately 70{%} are $β$ cells. A human pancreas contains about one million islets, which comprise only about 2{%} of the mass of the pancreas. Insulin is released into the portal vein, which means the liver is exposed to particularly high concentrations of insulin.