Glucagon

Glucagon is the body’s counter-regulatory hormone for falling blood glucose. It acts mainly on the liver, stimulating glycogenolysis and gluconeogenesis so glucose is released into the circulation. Emergency glucagon uses this same physiology. It is a rescue medication for severe hypoglycemia when oral carbohydrate is unsafe or impossible. Its effect depends on hepatic glycogen stores: glucagon can signal the liver to release glucose, but it cannot release glycogen that is no longer there. This limitation explains why glucagon may work poorly after prolonged fasting, starvation, substantial recent alcohol intake, advanced hepatic disease, adrenal insufficiency, chronic or recurrent hypoglycemia, or a very low-carbohydrate diet. In those situations, glucose given orally, if safe, or intravenously is more dependable.