Gastrin is a polypeptide hormone produced by G-cells in the gastric antrum and duodenal mucosa that serves as an important regulator of gastric acid secretion. The principal forms of gastrin in the stomach, which include big gastrin (G-34), small gastrin (G-17), and mini-gastrin (G-14), circulate in sulfated and nonsulfated forms.

 

Tests for the hormone gastrin, which is secreted by G cells of the gastric antrum and the pancreatic Islet of Langerhans, are used to investigate pernicious anemia and achlorhydria and to diagnose gastrinoma that is or is not associated Zollinger-Ellison syndrome.

Secretion of the hormone gastrin, by G cells of the gastric antrum and the pancreatic Islet of Langerhans, is stimulated by alkaline environment, vagal stimulation, and gastric distension, as well as by the presence of alcohol, amino acids, peptides, and calcium in the stomach. Gastrin secretion is inhibited by gastric acid.