G cell

In anatomy, the G cell is a type of cell in the stomach that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells.

G cells are found deep within the gastric glands of the stomach antrum, and occasionally in the pancreas.

The vagus nerve innervates the G cells.

Gastrin-releasing peptide is released by the post-ganglionic fibers of the vagus nerve onto G cells during parasympathetic stimulation. The peptide hormone bombesin also stimulates gastrin release from G cells.

Gastrin-releasing peptide, as well as the presence of amino acids in the stomach, stimulates the release of gastrin from the G cells. Gastrin stimulates enterochromaffin-like cells to release histamine.

Gastrin also targets parietal cells by increasing the amount of histamine and the direct stimulation by gastrin, causing the parietal cells to increase HCl secretion in the stomach.

Histomorphology
G cell have a distinctive microscopic appearance that allows one to separate them from other cells in the gastric antrum; their nucleus is centrally located in the cell and the cytoplasm is clear. They are found in the mid portion of the gastric glands.