Which endocrine cell of the gastric antrum secretes somatostatin, and what is its principal action on the parietal cell?

• A Enterochromaffin-like cell; potentiates histamine-driven cAMP generation
• B Chief cell; inhibits pepsinogen release through paracrine feedback
• C G cell; stimulates Ca2+-mediated exocytosis of HCl
• D D cell; inhibits adenylate cyclase via Gi, reducing cAMP and suppressing acid secretion ✓

Explanation

Antral B cells release somatostatin when luminal pH falls below about 3. Acting in paracrine fashion, it binds Gi-coupled receptors on G cells and parietal cells, lowering cAMP and shutting off acid secretion. ECL cells secrete histamine rather than somatostatin, and chief cells secrete pepsinogen.

Reference: Ganong's Review of Medical Physiology, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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