Hormone Biomarkers: Gastrin

Optimal Takeaways

The hormone gastrin supports the integrity and digestive function of the stomach, including gastric mucosa protection and hydrochloric acid production. Low levels can compromise digestion while high levels are associated with renal failure and gastrointestinal complications including, gastritis, gastric outlet obstruction, and carcinoma.

Standard Range: 0 - 100 pg/mL (0 - 48.1 pmol/L)

The ODX Range: 45 - 90 pg/mL (21.64 - 43.29 pmol/L)

Low serum gastrin may be seen with tricyclic antidepressants and anticholinergics (Pagana 2021), and in gastric bypass (Fatima 2021). Low levels may contribute to reduced hydrochloric acid output and compromised digestion and pathogen resistance.

High serum gastrin can be seen with Zollinger-Ellison syndrome, G-cell hyperplasia, gastric carcinoma, atrophic gastritis, pernicious anemia, peptic ulcer surgery, chronic renal failure, pyloric or gastric outlet obstruction, and ingestion of high-protein foods which can increase levels up to five times normal. Medications may increase serum gastrin including insulin, antacid peptic ulcer medication, and H2 blockers (Pagana 2021). Elevated gastrin can also be seen with Helicobacter pylori infection, gastrinoma (Fourmy 2011), and achlorhydria (Fatima 2021).

Overview

Gastrin is a gastrointestinal hormone present in the stomach and duodenum. It enhances growth of the gastric mucosa, promotes gastric motility, and stimulates secretion of hydrochloric acid, facilitating digestion. Gastrin is secreted in response to protein ingestion, gastric distension, and elevated gastric pH. Secretion decreases with a decreased gastric pH (Prosapio 2021).

Measurement of gastrin in the blood reflects the concentration of a variety of potentially bioactive peptides or “gastrins.” Serum gastrin levels in the fasting state are normally 62-104 pg/mL (30-50 pmol/L) with an increase to 208-312 pg/mL (100-150 pmol/L) following a meal. Gastrin levels may remain persistently high due to acid suppression therapy (Fourmy 2011). It is important to be sure gastrin measurement includes all bioactive gastrin peptides to avoid false low results (Rehfeld 2011).

Very high levels are seen in Zollinger-Ellison syndrome in which a pancreatic tumor produces excess gastrin. High levels are also seen when the G-cells in the distal stomach become hyperactive. Both conditions can lead to severe recurrent peptic ulcers. Routine peptic ulcers, however, will usually present with a normal serum gastrin (Pagana 2021). Production of gastrin is stimulated by a prolonged alkaline gastric environment and levels of gastrin as high as 500-1000 pg/mL (240-480 pmol/L) may be a sign of achlorhydria (Fatima 2021).

Excess gastrin can be pro-inflammatory and may enhance the carcinogenicity of H. pylori, a group 1 carcinogen (Chao 2010). Chronic proton-pump inhibitor therapy may increase serum gastrin to as high as 100-500 pg/mL (48-240 pmol/L), a level associated with increased enterochromaffin-like cell hyperplasia (Lundell 2015).

References

Chao, Celia, and Mark R Hellmich. “Gastrin, inflammation, and carcinogenesis.” Current opinion in endocrinology, diabetes, and obesity vol. 17,1 (2010): 33-9. doi:10.1097/MED.0b013e328333faf8

Fatima, Rawish. and Muhammad Aziz. “Achlorhydria.” StatPearls, StatPearls Publishing, 25 July 2021.

Fourmy, Daniel et al. “Gastrin in gastrointestinal diseases.” Gastroenterology vol. 141,3 (2011): 814-818.e1-3. doi:10.1053/j.gastro.2011.07.006

Lundell, L et al. “Systematic review: the effects of long-term proton pump inhibitor use on serum gastrin levels and gastric histology.” Alimentary pharmacology & therapeutics vol. 42,6 (2015): 649-63. doi:10.1111/apt.13324

Pagana, Kathleen Deska, et al. Mosby's Diagnostic and Laboratory Test Reference. 15th ed., Mosby, 2021.

Prosapio, Jordon G., et al. “Physiology, Gastrin.” StatPearls, StatPearls Publishing, 6 March 2021.

Rehfeld, Jens F et al. “The Zollinger-Ellison syndrome and mismeasurement of gastrin.” Gastroenterology vol. 140,5 (2011): 1444-53. doi:10.1053/j.gastro.2011.01.051