What is the primary function of glucagon?

• A. To lower blood glucose levels
• B. To raise blood glucose levels
• C. To stimulate fat storage
• D. To promote protein synthesis

Answer: (B)

The primary function of glucagon is to raise blood glucose levels. Glucagon is a hormone produced by the alpha cells of the pancreas that plays a critical role in maintaining glucose homeostasis, particularly during fasting or between meals. When blood sugar levels drop, glucagon is released into the bloodstream, signaling the liver to convert stored glycogen into glucose, which is then released into the bloodstream. This process is known as glycogenolysis. Additionally, glucagon promotes gluconeogenesis, the synthesis of glucose from non-carbohydrate sources, further increasing blood glucose levels.

In contrast, hormones or processes that lower blood glucose levels, such as insulin, are counter-regulatory to the actions of glucagon. Insulin facilitates the uptake of glucose by cells and stimulates storage of glucose as glycogen. Similarly, glucagon does not stimulate fat storage or promote protein synthesis; those processes are largely influenced by other hormones like insulin and growth hormone. Understanding the role of glucagon is essential for comprehending its impact on metabolic processes, particularly in conditions such as diabetes, where insulin regulation and blood glucose control are critical.