What is the primary effect of glucagon on blood sugar levels?

Glucagon primarily raises blood sugar levels by stimulating the liver to convert stored glycogen into glucose, a process known as glycogenolysis. When blood sugar levels drop, such as between meals or during periods of fasting, glucagon is released from the alpha cells of the pancreas. This hormone not only promotes the breakdown of glycogen but also encourages gluconeogenesis, which is the production of glucose from non-carbohydrate sources. As a result, glucagon plays a crucial role in maintaining blood glucose levels within a healthy range, especially during times when food intake is insufficient. This mechanism is vital for ensuring that the body has a consistent supply of energy, particularly for brain function, which relies heavily on glucose.