Gastrinreleasing

Gastrin releasing peptide (GRP) is a mammalian neuropeptide that stimulates the release of gastrin from G cells in the stomach’s antral mucosa. GRP is a bombesin-like peptide produced mainly by enteric neurons and some central neurons, and it acts as a signaling molecule in the regulation of gastric function. It binds to the gastrin releasing peptide receptor (GRPR) on G cells, promoting gastrin secretion into the portal circulation.

Gastrin, once released, acts to stimulate gastric acid secretion by parietal cells through a pathway that involves histamine release from enterochromaffin-like (ECL) cells and direct trophic effects on the gastric mucosa. In addition to acid secretion, gastrin supports mucosal growth in the stomach and contributes to the regulation of gastric motility. Gastrin release is influenced by multiple factors, including vagal stimulation, luminal peptides and amino acids, and stomach distension. Negative feedback is mediated by lowered gastric pH, which stimulates somatostatin release from D cells to inhibit gastrin release.

Clinical relevance includes conditions of dysregulated gastrin secretion, such as Zollinger-Ellison syndrome, where gastrin-producing tumors (gastrinomas) cause excessive acid production and peptic ulcers. GRP and GRPR have been explored in research contexts for their roles in gastroenterology and oncology, including potential diagnostic or therapeutic implications, though routine clinical use remains limited. Understanding GRP’s role in gastrin release contributes to broader insights into the control of gastric acid secretion and mucosal homeostasis.