Also the basal mechanisms underlying the secretion of insulin have been identified. The level of blood glucose controls the level of glucose within the insulin-forming cell, which in turn regulates the level of the energy rich substance ATP. ATP acts directly on a particular type of ion channel which controls the electric membrane potential of the cell. The change of membrane potential then indirectly influences other ion channels, which permit calcium ions to pass into the cell. The calcium ions subsequently trigger the insulin secretion. In diabetes the insulin secretion is out of order. Certain drugs commonly used to stimulate insulin secretion in diabetes act directly on the ATP-controlled ion channels