Cholecystokinin 5 (CCK5)

Pentagastrin is a synthetic polypeptide that has effects like gastrin when given parenterally. It stimulates the secretion of gastric acid, pepsin, and intrinsic factor, and has been used as a diagnostic aid as the pentagastrin-stimulated calcitonin test.Pentagastrin binds to the cholecystokinin-B receptor, which is expressed widely in the brain. Activation of these receptors activates the phospholipase C second messenger system. When given intravenously it causes panic attacks.Pentagastrin is also used as a stimulation test to elevate serotonin levels and cause symptoms of carcinoid syndrome. It provokes flushing and is useful in evaluating patients who describe flushing, but have normal or only marginally elevated biochemical markers for carcinoid syndrome. In addition, it has been used to stimulate ectopic gastric mucosa for the detection of Meckels diverticulum by nuclear medicine.