What is the role of gastrin?

• A. Regulates digestion by maintaining normal pH.
• B. Stimulates insulin release.
• C. Facilitates digestion in the stomach.
• D. Stimulates adrenal secretion.

Answer: (C)

Gastrin is a hormone released by G cells in the stomach in response to food, especially peptides and stomach distension. It acts mainly to promote digestion in the stomach by stimulating acid secretion from parietal cells (and pepsinogen release from chief cells), which creates the acidic environment needed to unfold proteins and activate pepsin. This setup also supports stomach motility and mucosal growth, all of which facilitate gastric digestion. So, the role described—facilitating digestion in the stomach—is the best fit. The other options describe functions not driven by gastrin: insulin release is from the pancreas in response to glucose, adrenal secretion is governed by other hormonal pathways, and maintaining a normal pH is a broader process not specifically accomplished by gastrin alone.