Gastrina

Gastrin and the vagal nerves are the main regulators of gastric acid secretion. However other factors than gastrin contribute to the gastric acid
secretion. The main site for gastrin production is the antropyloric mucosa of the stomach. A few gastrin producing cells may also be found in the
duodenum and pancreas.
Gastrin occurs in many different forms in human serum. An amidated C-terminal is essential for the biological activity of the gastrins.
Progastrin is cleaved from preprogastrin. It has been shown that progastrin is partially sulphated in the tyrosine residues. The progastrin is enzymatically
cleaved to the main circulating forms of biologically active gastrin: gastrin-34 and gastrin-17, which occur in sulphated an non-sulphated
forms. Small amount of gastrin-52 (also named component 1), gastrin-14 (mini-gastrin) and even smaller fragments have been detected in serum.