Gastroenterology is a specialty that has been gaining increasing prominence in veterinary medicine, in line with the demand for specialized professionals and tools that contribute to more accurate diagnoses.
In clinical practice, gastrointestinal abnormalities may be related to various conditions, and in some patients, hormonal testing can help broaden the diagnostic workup. Among the hormones of interest is gastrin, a marker that links endocrinology to the physiology of the digestive system, but which remains underutilized in the routine diagnostic workup of dogs and cats.
What is gastrin?
Gastrin is a peptide hormone produced primarily by G cells located in the gastric antrum. Its main function is to stimulate, either directly or indirectly, the secretion of hydrochloric acid (HCl) by the parietal cells of the stomach.
The release of gastrin is part of a complex physiological mechanism related to digestion. It plays a key role in preparing the gastrointestinal system for food processing and helps regulate gastric activity.
Because of their relationship to gastric acid secretion, changes in gastrin levels can provide important information during the investigation of certain gastrointestinal and endocrine disorders.
When might a gastrin test be recommended?
Gastrin testing in dogs and cats may be considered when evaluating patients with persistent or recurrent gastrointestinal signs, especially when the cause is not clearly established.
Situations that may warrant this investigation include:
- Chronic or refractory vomiting;
- Recurrent gastric or duodenal ulcers;
- Chronic abdominal pain;
- Unexplained weight loss;
- Melena;
- Anemia of unknown cause;
- Suspected acid hypersecretion;
- Gastrinoma investigation;
- Monitoring of patients on long-term treatment with medications that reduce gastric acid secretion.
The decision to order the test should always take into account the individual clinical presentation and other findings from the evaluation. Medication history should also be assessed, as certain drugs can interfere with gastrin levels.
When should you request a gastrin test?
High gastrin levels—what could that mean?
An elevated concentration of gastrin in the blood is called hypergastrinemia and may be associated with various medical conditions.
One possibility is a gastrinoma, a rare neuroendocrine tumor that causes excessive production of gastrin and can lead to hypersecretion of gastric acid. Increased acid secretion can contribute to the development of lesions in the gastrointestinal tract, including gastric and duodenal ulcers.
However, hypergastrinemia is not necessarily related to the presence of a neoplasm. It can also occur secondarily, including in patients taking medications that reduce gastric acid secretion. In such cases, the reduction in gastric acidity may stimulate compensatory mechanisms, increasing G-cell activity and, consequently, gastrin concentration.
Clinical Consideration
The interpretation of elevated gastrin levels in dogs and cats should take into account the patient’s clinical and medication history, in addition to the other test results.
Gastrin and Long-Term Use of Antacids
Medications used to reduce gastric acid secretion may interfere with the physiological mechanisms that regulate gastrin production.
A prolonged reduction in stomach acidity may stimulate G-cell activity as a compensatory mechanism, leading to an increase in the hormone’s concentration. For this reason, the use of medications that interfere with gastric secretion should be considered when evaluating patients with hypergastrinemia.
Information such as the type of medication used, the dose, the duration of treatment, and the clinical indication is important for a proper interpretation of the results.
In these cases, measuring gastrin can serve as a complementary tool.
Do you have questions about which medications affect gastric secretion?
The Importance of Gastrin Testing in Veterinary Practice
Incorporating gastrin into clinical reasoning allows for a more precise investigation of cases that often remain unexplained based solely on conventional tests.
At Hormonalle, we offer gastrin measurement via radioimmunoassay (RIA) for dogs and cats. Interpretation of the results should always take into account the individual clinical context, medication history, and other tests performed during the evaluation.
Would you like to request a gastrin test?
Bibliographic References
FELDMAN, E. C.; NELSON, R. W.; REUSCH, C. E.; SCOTT-MONCRIEFF, J. C.; BEHREND, E. N. Canine and Feline Endocrinology. 5th ed. St. Louis: Elsevier, 2025.
MOONEY, C. T.; PETERSON, M. E. BSAVA Manual of Canine and Feline Endocrinology. 4th ed. Gloucester: BSAVA, 2012.
NELSON, R. W.; COUTO, C. G. Small Animal Internal Medicine. 6th ed. St. Louis: Elsevier, 2020.
Can gastrin be used on its own to diagnose a gastrinoma?
No. Elevated gastrin levels are suggestive of the diagnosis but do not confirm it on their own; other causes of secondary hypergastrinemia must first be ruled out. Confirmation of a gastrinoma generally depends on the association with imaging findings, a compatible clinical history, and, in some cases, additional provocation tests.
Can medications affect the results of a gastrin test?
Yes. Medications that reduce gastric acid secretion can trigger compensatory mechanisms and contribute to an increase in gastrin levels. For this reason, it is important to inform the veterinarian of all medications the patient is taking before interpreting the test results.
How long before the exam should I stop taking antacids?
There is no single timeframe that applies to all cases; it depends on the class of medication, the dose, and the patient’s clinical condition, and the decision to discontinue (or not) should always be made by the attending veterinarian.
Is gastrinoma curable? What role does gastrin play in follow-up care?
When diagnosed early and completely resectable, a gastrinoma may have a good prognosis after surgery. In such cases, monitoring gastrin levels over time can help identify recurrence or residual tumor tissue, serving as a complementary tool in postoperative monitoring.