Which hormone is responsible for breaking down glycogen to create glucose?

The hormone responsible for breaking down glycogen to create glucose is glucagon. It is produced by the alpha cells of the pancreas and plays a critical role in glucose metabolism. When blood glucose levels are low, glucagon is released into the bloodstream and acts primarily on the liver.

In the liver, glucagon stimulates the process of glycogenolysis, which is the breakdown of glycogen, the stored form of glucose. This process yields free glucose molecules that can be released into the bloodstream, thereby raising blood glucose levels and providing energy to the body's cells.

Understanding the functions of glucagon helps clarify its importance in maintaining glucose homeostasis, especially during fasting or between meals when the body needs to access stored energy. In contrast, insulin, produced by the beta cells of the pancreas, functions to lower blood glucose levels by facilitating the uptake of glucose into cells and promoting glycogen synthesis, rather than breaking it down. Cortisol and adrenaline also have roles in glucose metabolism, particularly during stress, but they do not specifically act to break down glycogen directly.