Pentagastrin

Pentagastrin

Chemical structure of pentagastrin

Pentagastrin is a synthetic peptide that mimics the action of the naturally occurring hormone gastrin. It is primarily used in diagnostic tests to assess gastric acid secretion and to evaluate the function of the stomach and pancreas.

Structure and Composition

Pentagastrin is composed of five amino acids, making it a pentapeptide. Its sequence is _-Ala-His-Trp-Met-Asp-Phe-NH2. The structure of pentagastrin allows it to bind to the cholecystokinin B receptor (CCK-B receptor), which is also the receptor for gastrin.

Mechanism of Action

Pentagastrin acts by stimulating the parietal cells in the stomach lining to secrete hydrochloric acid. This is similar to the action of gastrin, which is a hormone that regulates gastric acid secretion. By binding to the CCK-B receptor, pentagastrin triggers a cascade of intracellular events that lead to increased acid production.

Clinical Uses

Pentagastrin is used in various diagnostic tests, including:

• Gastric Acid Secretion Test: To measure the amount of acid produced by the stomach, helping diagnose conditions like Zollinger-Ellison syndrome.
• Calcitonin Stimulation Test: Used in the diagnosis of medullary thyroid carcinoma, as pentagastrin can stimulate the release of calcitonin from the thyroid gland.

Administration

Pentagastrin is typically administered via intravenous injection. The dosage and administration depend on the specific diagnostic test being conducted.

Side Effects

Common side effects of pentagastrin administration include:

• Abdominal discomfort
• Nausea
• Flushing
• Dizziness

These side effects are generally mild and transient.

Related Pages

• Gastrin
• Cholecystokinin
• Zollinger-Ellison syndrome
• Medullary thyroid carcinoma