What role does glucagon play in glucose metabolism?

• A. It decreases blood glucose levels
• B. It increases glucose levels by promoting glycogen breakdown
• C. It converts glucose to fat
• D. It stimulates liver function

Answer: (B)

Glucagon plays a critical role in glucose metabolism by increasing glucose levels in the blood. When blood sugar levels drop, such as between meals or during fasting, glucagon is secreted by the alpha cells of the pancreas. This hormone prompts the liver to break down glycogen, a stored form of glucose, into glucose molecules through a process known as glycogenolysis. Additionally, glucagon can enhance gluconeogenesis, which is the production of glucose from non-carbohydrate sources. By promoting these processes, glucagon helps elevate blood glucose levels, ensuring that the body has a sufficient energy supply, especially for vital organs like the brain. This mechanism is fundamental in maintaining glucose homeostasis and counterbalancing the effects of insulin, which lowers blood glucose levels.

The functions of glucagon, particularly its ability to increase glucose availability, highlight its essential role in regulating metabolism, especially during periods of low blood sugar.