Gastrin I (human)

Gastrin I is an endogenous, gastrointestinal peptide hormone that binds to cholecystokinin (CCK) receptors on human gastric leiomyosarcoma cells (IC50 = 0.9 nM) and in guinea pig gallbladder and pancreatic tissue (IC50s = 1.7 and 2.5 ?M, respectively).{36434,36435} It increases levels of cytosolic calcium in isolated rabbit stomach parietal cells (EC50 = 11 nM) and stimulates pepsinogen secretion by isolated human peptic cells (ED50 = 30 nM).{36436,36437} Gastrin I increases histidine decarboxylase (HDC) activity ex vivo in fundic stomach mucosa homogenate and increases gastric acid secretion in vivo in rats when administered at a dose of 1 nmol/kg/h.{36438}