Where is glucagon produced, and what is its intracellular effect?

Where is glucagon produced, and what is its intracellular effect?

• A. Adrenal gland; increases intracellular calcium
• B. Liver; decreases cAMP
• C. Pancreas; increases cAMP
• D. Pancreas; decreases cAMP

Answer: (C)

Glucagon is produced by pancreatic alpha cells. It acts on liver cells using a Gs-coupled receptor, which activates adenylyl cyclase and raises intracellular cAMP. That increase in cAMP activates protein kinase A, driving processes like glycogenolysis and gluconeogenesis to raise blood glucose. The adrenal gland is not the source of glucagon, and the intracellular effect is an increase, not a decrease, in cAMP. So the correct pairing is pancreas production with an increase in cAMP.

Glucagon is produced by pancreatic alpha cells. It acts on liver cells using a Gs-coupled receptor, which activates adenylyl cyclase and raises intracellular cAMP. That increase in cAMP activates protein kinase A, driving processes like glycogenolysis and gluconeogenesis to raise blood glucose. The adrenal gland is not the source of glucagon, and the intracellular effect is an increase, not a decrease, in cAMP. So the correct pairing is pancreas production with an increase in cAMP.