What action does glucagon perform to raise blood glucose?

What action does glucagon perform to raise blood glucose?

• A. Stimulates glucose uptake by tissues
• B. Converts glycogen to glucose in the liver and releases glucose into the bloodstream
• C. Inhibits glycogenolysis
• D. Stimulates insulin secretion

Answer: (B)

Glucagon raises blood glucose by signaling liver cells to break down stored glycogen into glucose and release it into the bloodstream. This glycogenolysis in the liver increases circulating glucose, especially between meals. The process is driven by a cAMP signaling cascade that activates glycogen phosphorylase and promotes glucose export from the liver. The liver is the key source because skeletal muscle cannot release glucose to the blood. In contrast, the other options describe actions that would lower blood glucose or block glucose release: stimulating glucose uptake would lower sugar levels (insulin-like action), inhibiting glycogenolysis would prevent glucose release, and stimulating insulin secretion would also lower blood glucose.

Glucagon raises blood glucose by signaling liver cells to break down stored glycogen into glucose and release it into the bloodstream. This glycogenolysis in the liver increases circulating glucose, especially between meals. The process is driven by a cAMP signaling cascade that activates glycogen phosphorylase and promotes glucose export from the liver. The liver is the key source because skeletal muscle cannot release glucose to the blood. In contrast, the other options describe actions that would lower blood glucose or block glucose release: stimulating glucose uptake would lower sugar levels (insulin-like action), inhibiting glycogenolysis would prevent glucose release, and stimulating insulin secretion would also lower blood glucose.