Purity ~95%. Purified by HPLC. In humans, gastrin is a hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility. It is 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,[1][2] and gastrins were isolated in 1964 by Gregory and Tracy in Liverpool.[3] The GAS gene is located on the long arm of the seventeenth chromosome (17q21).[4] Gastrin is a linear peptide hormone produced by G cells of the duodenum and in the pyloric antrum of the stomach. It is secreted into the bloodstream. Gastrin is found primarily in three forms: gastrin-34 ('big gastrin'), gastrin-17 ('little gastrin') and gastrin-14 ('minigastrin'). Also, pentagastrin, a five amino acid sequence artificially synthesized peptide, has a five amino acid sequence identical to the last five amino acid sequence at the C-terminus end of gastrin. Gastrin is released in r