Gastrin

Hypergastrinemia occurs when levels of gastrin become higher than usual. Gastrin is a hormone that affects the levels of gastric acid in your stomach. Hypergastrinemia has many causes, including long-term use of PPIs and antacids, H. pylori infection, gastritis and Zollinger-Ellison syndrome. Treatment involves managing the underlying cause. Too much gastrin can causes severe peptic ulcer disease.

Medicines that can increase gastrin level include:

- Stomach acid reducers, such as antacids

- H2 blockers (cimetidine and famotidine)

- Proton pump inhibitors (omeprazole and pantoprazole)

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A higher than normal level may also be due to:

- Chronic kidney disease
- Long-term gastritis
- Over-activity of the gastrin-producing cells in the stomach (G-cell hyperplasia)
- Helicobacter pylori infection of the stomach
- Use of antacids or medicines to treat heartburn
- Zollinger-Ellison syndrome, a gastrin-producing tumor that may develop in the stomach or pancreas
- Decreased ability of the stomach to produce acid
- Previous stomach surgery

By far, the two most common causes of high gastrin levels are 1) anti-acid medications you take for reflux or heartburn and 2) a condition called chronic atrophic gastritis. These both can do damage to your stomach lining. They also cause your stomach to make less acid. In these settings, the gastrin level increases because the pH of your stomach is too high (alkaline). The pH scale measures how acidic something is.

A gastrin level that’s too high may be caused by a condition called Zollinger-Ellison (ZE) syndrome. This could mean you have a tumor in your digestive system that’s secreting gastrin. These tumors are called gastrinomas. They’re normally located in the first part of your small intestine (the duodenum) or in your pancreas. The extra gastrin can cause too much acid in your digestive system. This can trigger diarrhea and may lead to ulcers in your stomach and small intestine.

If you had a gastrinoma that was removed through surgery and your test results show an increase in gastrin, it may mean the tumor has returned. If your gastrin levels didn’t go down at all after surgery, it could mean the procedure wasn’t successful.

Elevated gastrin levels should be interpreted in light of gastric acid secretion and other parameters. The neuroendocrine tumors associated with the Zollinger-Ellison syndrome are characterized by elevated rates of gastric HCl secretion and upper gastrointestinal ulcer disease. Gastrin levels >500-600 pg/mL in someone with basal acid hypersecretion often indicate gastrinoma, but antral G-cell hyperplasia cases can have gastrin levels >500 pg/mL and hyperchlorhydria.

The Gastrin test is a simple blood test that checks for excess gastrin production. Gastrin is a hormone your stomach makes to fuel the release of gastric acid. Your body needs this to digest and absorb nutrients in your food, particularly proteins and amino acids. 

Gastric acid is found inside cells called G cells. These are located in your stomach lining and the lining of your upper small intestine.