In humans, gastrin's a hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility. It's released by G cells in the stomach, duodenum, and the pancreas. Its existence was first suggested in 1905 by the British physiologist John Sydney Edkins, and gastrins were isolated in 1964 by Gregory and Tracy in Liverpool. Physiology Genetics The GAS gene's located on the long arm of the seventeenth chromosome (17q21). Synthesis Gastrin's a line… (More on Gastrin)