Gastrin is a hormone produced by the stomach that plays a crucial role in digestion. It stimulates the secretion of gastric acid, which helps break down food and aids in the absorption of nutrients. Gastrin is released in response to food intake, particularly proteins, and helps regulate the digestive process. In addition to its role in acid secretion, gastrin also promotes the growth of the stomach lining and enhances gastric motility, which is the movement of food through the digestive tract. Abnormal levels of gastrin can lead to digestive disorders, such as Zollinger-Ellison syndrome, characterized by excessive gastric acid production.