Hormone secreted by stomach cells that signals glands in stomach to release gastric juice?

• A. Gastrin
• B. Secretin
• C. Cholecystokinin
• D. Ghrelin

Answer: (A)

Gastrin is the hormone released by cells in the stomach lining, especially in the antrum, when food is present. It signals the gastric glands to ramp up gastric juice production by stimulating parietal cells to secrete hydrochloric acid and by promoting pepsinogen release from chief cells (with histamine helping further acid release). This coordinated acid and enzyme secretion prepares the stomach for digestion. Other options act in different contexts: secretin comes from the small intestine to neutralize acid and dampen gastric activity; cholecystokinin from the small intestine promotes pancreatic enzyme release and bile flow while slowing gastric emptying; ghrelin mainly stimulates appetite rather than gastric juice secretion.