Pancreas release both insulin as well as glucagon, but there release depends on different glucose levels in bloodstream. When blood glucose concentration increases, in response to it Insulin is released by the beta cells in the islets of Langerhans.
Role of insulin: i) it lower glucose levels in the bloodstream, ii) it also promote the storage of glucose in muscle, liver and other parts o the body .
While alpha cells in the islets of Langerhans produce glucagon when glucose concentration decreases in the blood.
