insulin

a pancreatic HORMONE , produced in the ISLETS OF LANGERHANS , that initiates uptake of glucose by body CELLS and thereby controls the level of glucose in the blood. It works by stimulating proteins on cell surfaces within muscles and other TISSUE to take up glucose for their activity. A lack of hormone results in the sugar derived from food being excreted in the urine - the condition DIABETES MELLITUS . In such cases, insulin can be administered by injection.