What it is
Gastrin is a peptide hormone made in the lower stomach, and its job is to switch on acid. UniProt's summary (P01350) describes it as stimulating the stomach lining to produce and secrete hydrochloric acid and the pancreas to secrete digestive enzymes.
It is not one fixed length. A 101-residue precursor is cut into a family of peptides — gastrin-71, -52, -34, -17, -14 and -6 — and UniProt names two as the major bioactive forms: gastrin-34 ("big gastrin") and gastrin-17. Gastrin-17 reads:
pE-GPWLEEEEEAYGWMDF-NH2
The "pE" is a pyroglutamate, a ring-closed glutamine; the end is capped as an amide. The tyrosine near the end is only sometimes sulfated: UniProt reports gastrin-6 at almost 73% sulfated and the larger gastrins at under 50%.
Where it is made and what it acts on
UniProt places its production in the G cells of the antrum, the lower part of the stomach. It acts on the CCKBR receptor (also called the CCK2 receptor), which UniProt describes as the receptor for both gastrin and cholecystokinin.
That shared receptor has a visible cause. Lining up the two hormones' sequences from UniProt, gastrin and cholecystokinin end in the same five amino acids:
| Peptide (UniProt) | Last residues |
|---|---|
| Gastrin-17 (P01350) | …EEEEEAYGWMDF-NH2 |
| Cholecystokinin-8 (P06307) | DYMGWMDF-NH2 |
UniProt places both in the "gastrin/cholecystokinin family".
How it was found
The idea of a gastric hormone goes back to J. S. Edkins, whose paper "The chemical mechanism of gastric secretion" appeared in the Journal of Physiology in 1906 (PMID 16992839). The structure came almost six decades later: two papers in Nature on 5 December 1964 — one by Anderson and colleagues on the synthesis of gastrin, one by Tracy and Gregory on the physiological properties of related synthetic peptides (PMIDs 14248712, 14248713).
What raises it: acid suppression
Gastrin and acid move in opposite directions: suppress the acid and gastrin climbs. The clearest dated statement is on the Prilosec label (Covis, effective 2024-03-19):
- In studies of more than 200 patients, serum gastrin rose during the first 1–2 weeks of once-daily omeprazole, in parallel with acid suppression, and rose no further with continued treatment.
- The label adds that raised gastrin causes enterochromaffin-like cell hyperplasia and raises serum chromogranin A.
- It warns that acid suppression can produce a hyper-response in a secretin stimulation test, "falsely suggesting gastrinoma", and sets a gap of at least 14 days off the drug before gastrin is assessed.
That warning is the practical reason the medicine list matters when a gastrin test is read.
When it is measured: gastrin-making tumours
In 1955 Zollinger and Ellison described ulcers in the jejunum occurring with tumours of the pancreatic islet cells (Annals of Surgery, PMID 13259432). In 1964 Gregory reported on "the nature of the gastrin-like stimulant present in Zollinger–Ellison tumours" (Gut, PMID 14159397). The tumour, a gastrinoma, makes gastrin, and the excess gastrin makes excess acid.
So a gastrin blood test is chiefly a tumour question, and its reading depends on context: whether the person was fasting, whether acid suppressants were in use, and what other tests show. Each of those is decided by the clinician who ordered it; this entry does not give a normal range or say what any individual number means.
Where it stands
- As a medicine: none. Drugs@FDA returns no application with gastrin as an active ingredient (2026-10-06; the same search returns semaglutide's applications, so the query works). Pentagastrin, sold as Peptavlon (Wyeth-Ayerst, NDA 017048, approved 1974-07-26), is listed as discontinued.
- Drugs that act on its pathway: acid suppressants raise it; somatostatin analogues lower it — the octreotide and lanreotide labels both list gastrin among the hormones suppressed.
- Research record: PubMed indexes 17,090 records with "gastrin" in the title or abstract, 459 tagged as randomised trials (2026-10-06) — most measure gastrin as an outcome rather than test it as a treatment.
Related reading
The hormone that brakes gastrin is in the somatostatin entry, and the drug that copies it — whose label lists gastrin among the hormones it suppresses — is described in the Sandostatin entry, octreotide. The somatostatin analogue lanreotide also suppresses gastrin after meals, per its label.