- Gastrin is a peptide hormone synthesized by G cells located within pyloric glands of the gastric antrum and displays multiple affects on the stomach.
- Several stimuli directly act on G Cells to induce their release of gastrin. These include the local presence of protein and amino acids as well as physical expansion of the stomach by the presence of food. Additionally, release of GRP onto G Cells by efferents of the vagus nerve induces gastrin release.
- Stimulation of Stomach Acid Secretion
- Gastrin acts directly on parietal cells to stimulate their release of stomach acid. It should be pointed out that this action of gastrin is coordinated with other stimuli acting on parietal cells as described in stomach acid secretion.
- Trophic effect on Gastric Mucosa
- Long-term maintenance of the gastric mucosa requires the presence of gastrin. Therefore, resection of the gastric antrum where G Cells exist will eventually yield atrophy of the entire gastric mucosa. Conversely, gastrin-secreting adenomas that cause Zollinger-Ellison Syndrome also result in hypertrophy of the entire gastric mucosa.