What is the role of glucagon in glucose regulation?

Glucagon plays a crucial role in glucose regulation, particularly when blood sugar levels are low. Its primary function is to raise blood sugar levels by promoting glycogenolysis and gluconeogenesis in the liver. Glycogenolysis is the process of breaking down glycogen, a stored form of glucose, into glucose, which then enters the bloodstream, thereby elevating blood sugar levels. Additionally, glucagon stimulates the liver to produce new glucose molecules from non-carbohydrate sources in a process called gluconeogenesis.

The action of glucagon is particularly important during fasting or between meals when blood glucose levels can drop. By counteracting the effects of insulin, which lowers blood glucose levels, glucagon ensures that the body has a sufficient supply of glucose for energy, especially for the brain and other critical organs that rely on glucose as their primary energy source. This balance between insulin and glucagon is vital for maintaining homeostasis in blood glucose levels.