What is the primary function of glucagon in the human body?

Glucagon is a hormone produced by the pancreas, specifically by the alpha cells, and its primary function is to raise blood sugar levels. It is released when blood glucose levels fall below a certain threshold, signaling the body that it needs to mobilize energy reserves.

When glucagon is secreted, it prompts the liver to convert stored glycogen into glucose through a process known as glycogenolysis. This glucose is then released into the bloodstream, effectively raising blood sugar levels and providing energy for bodily functions. In addition to this, glucagon can also stimulate gluconeogenesis, which is the production of glucose from non-carbohydrate sources, further contributing to the increase in blood glucose levels.

The role of glucagon is essential for maintaining homeostasis in energy metabolism, especially during fasting or between meals, when blood sugar levels can drop. This hormonal action ensures that the body has a steady supply of glucose, which is critical for the proper functioning of cells, particularly those in the brain that rely on glucose as their primary energy source.