What is the primary function of glucagon in the body?

Glucagon's primary function in the body is to increase blood sugar levels, particularly during periods of fasting or low carbohydrate intake. It is a hormone produced by the alpha cells of the pancreas that acts as a counter-regulatory hormone to insulin. When blood glucose levels drop, glucagon is released into the bloodstream.

The hormone stimulates the liver to convert stored glycogen into glucose—a process known as glycogenolysis—and to synthesize new glucose from non-carbohydrate sources, a process called gluconeogenesis. As a result, these actions contribute to raising blood sugar levels back to a normal range, ensuring that the body has a continuous supply of glucose, which is a critical energy source for many cells, especially those in the brain and muscles.

The function of glucagon is crucial for maintaining blood sugar homeostasis, particularly during fasting or between meals, when the body's glucose needs must be met despite the lack of direct intake.