Which hormone inhibits gastric acid secretion and stimulates insulin release in response to glucose?

• A. Secretin
• B. GIP
• C. Gastrin
• D. Somatostatin

Answer: (B)

GIP, or gastric inhibitory peptide, is released by K cells in the small intestine when nutrients like glucose enter the gut. It has a dual action: it stimulates insulin release from pancreatic beta cells in a glucose-dependent way, helping the body handle the rise in blood glucose after a meal, and it inhibits gastric acid secretion to slow down the emptying of the stomach and protect the intestine from too much acid. This combination fits the prompt exactly—the hormone responds to glucose by boosting insulin and also dampens acid production.

Secretin mainly stimulates pancreatic bicarbonate secretion to neutralize acid in the duodenum and isn’t known for boosting insulin. Gastrin drives acid secretion from the stomach, not insulin release. Somatostatin broadly inhibits many secretions, including insulin and acid, so it wouldn’t be the right match for both actions.