Britannica Sources used in this answer

How does gastrin affect gastric juice secretion?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram of the human digestive system viewed from the front, showing and labeling organs including the mouth, teeth, tongue, salivary glands, pharynx, esophagus, liver, stomach, gallbladder, pancreas, large intestine, small intestine, appendix, rectum, and anus. — digestion The human digestive system as seen from the front.

Gastrin is a hormone that plays a critical role in regulating the production of gastric juice when food enters the stomach.1

When food enters the stomach, it triggers the release of gastrin from G cells located in the antrum into the bloodstream. Once in circulation, gastrin travels to the body of the stomach and binds to specific receptor sites on the outer membrane of parietal cells. This binding process triggers an energy-consuming reaction that stimulates these cells to secrete hydrogen ions, which combine with chloride ions to form hydrochloric acid.21

In addition to promoting acid production, gastrin facilitates the secretion of pepsinogen, a precursor to the protein-digesting enzyme pepsin. By stimulating these components, gastrin ensures the stomach is prepared to break down food and eliminate ingested bacteria. Furthermore, gastrin increases stomach motility, which assists in churning food and moving it through the digestive tract.1