What effect does glucagon have on the body?

Glucagon is a hormone produced by the alpha cells of the pancreas that plays a crucial role in regulating blood glucose levels, especially during fasting or between meals. When blood glucose levels drop, glucagon is released into the bloodstream, where it exerts its primary effect by stimulating glycogenolysis, the process of breaking down glycogen into glucose in the liver. This action increases the concentration of glucose available in the blood, countering low blood sugar levels.

In addition to this, glucagon can also stimulate gluconeogenesis, which is the synthesis of glucose from non-carbohydrate sources. These effects collectively work to elevate blood glucose levels and ensure that the body has a readily available energy source, especially crucial for energy-demanding organs like the brain.

The other options represent processes that are not initiated by glucagon. For instance, stimulating protein synthesis is more commonly associated with insulin, which promotes nutrient storage and utilization. Inhibiting glucose release would also not align with glucagon's function, as its primary action is to promote the release of glucose. Reducing blood sugar levels is primarily the role of insulin rather than glucagon, which serves the opposite function. Therefore, the correct answer highlights glucagon’s key role in stimulating glycogen breakdown to