Gastrin stimulates the stomach mucosa to produce and secrete hydrochloric acid and the pancreas to secrete its digestive enzymes. It also stimulates smooth muscle contraction and increases blood circulation and water secretion in the stomach and intestine. Two different processing pathways probably exist in antral G-cells. In the dominant pathway progastrin is cleaved at three sites resulting in two major bioactive gastrins, gastrin-34 and gastrin-17. In the putative alternative pathway, progastrin may be processed only at the most C-terminal dibasic site resulting in the synthesis of gastrin-71. Sulfation enhances proteolytic processing, and blocks peptide degradation. Levels of sulfation differ between proteolytically-cleaved gastrins. Thus, gastrin-6 is almost 73% sulfated, whereas the larger gastrins are less than 50% sulfated. Sulfation levels are also tissue-specific. Belongs to the gastrin/cholecystokinin family. Gastrin entry