Gastrin

Latest Edit: Hector 2014-03-24 (EDT)

See Also	Lab Tests

The gastrin test is used to evaluate patients with peptic ulcers in order to help diagnose Zollinger-Ellison (ZE) syndrome or G-cell hyperplasia.

Discussion

• Gastrin is a hormone produced by the G cells which are located in the distal part of the stomach.
• It is a potent stimulator of gastric acid.
• An alkaline environment (created by food and antacids) stimulates the release of gastrin, which then stimulates the parietal cells of the stomach to secrete gastric acid. This subsequently reduces the pH environment of the stomach.
• ZE syndrome and G-cell hyperplasia are two conditions which are associated with high serum gastrin levels.

Patient Preparation

• Fasting is required for 12 hours before the test. Water is permitted.
• Alcohol should be avoided for at least 24 hours before the test.

• Factors which can cause increased levels

• Peptic ulcer surgery
• Ingestion of high-protein foods
• Diabetic patients taking insulin may have falsely elevated levels in response to hypoglycemia
• Calcium may increase gastrin levels by acting as a gastrin stimulant
• Drugs: antacids, H2- blocking agents (e.g. Tagamet, Zantac), and hydrogen pump inhibitors (e.g. Prilosec), catecholamines, coffee

• Factors which can cause decreased levels

• Drugs: anticholinergics, tricyclic antidepressants

Clinical Implications

High levels indicate:

• ZE syndrome
• G-cell hyperplasia
• Pernicious anemia
• Atrophic gastritis
• Gastric carcinoma
• Chronic renal failure
• Pyloric obstruction or gastric outlet obstruction
• Retained antrum after gastric surgery

Low levels indicate:

• None noted

Associated Tests

• Gastric analysis, H. pylori