Somatostatin secreted by pancreatic delta cells exerts which paracrine effect within the islet?

• A Stimulates both insulin and glucagon secretion
• B Inhibits insulin secretion only
• C Inhibits both insulin and glucagon secretion ✓
• D Stimulates glucagon secretion and inhibits insulin secretion

Explanation

Delta cells scattered within the islets secrete somatostatin, which acts locally through Gi-coupled receptors to suppress secretion of both insulin from beta cells and glucagon from alpha cells, damping overall islet output after nutrient ingestion. Its secretion is stimulated by glucose, amino acids, and gut hormones. This dual inhibition distinguishes it from intra-islet effects such as insulin suppressing glucagon alone.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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