Glucagon

Glucagon is a hormone that raises the level of glucose (sugar) in the blood by causing the liver to release its intracellular stores of glucose. Normally, the alpha cells of the pancreas (in areas called the Islets of Langerhans) make glucagon when in response to hypoglycaemia in the body. An injectable form of glucagon, which can be bought in a drug store, is sometimes used to treat insulin shock. The glucagon is injected and quickly raises blood glucose levels. It works only if there is glucose stored in liver cells, and it won't work again until those stores are replenished.