What it is
Cholecystokinin — CCK — is a peptide hormone made in the small intestine that tells the gallbladder to squeeze and the pancreas to release digestive enzymes. The name says it: Greek for "moving the gallbladder".
Like many gut hormones it is made as a longer precursor and cut to size. UniProt (P06307) records a 115-residue precursor and lists the active pieces by length: CCK-58, -39, -33, -25, -18, -12, -8, -7 and -5. Every one ends at the same point, so they share the same tip:
CCK-8: D-Y-M-G-W-M-D-F-NH2 (residues 96–103), with the tyrosine carrying a sulfate group and the final phenylalanine amidated. UniProt notes CCK is also detected in cerebrospinal fluid.
How it works
UniProt's function annotation names two receptors:
| Receptor | What binding does (UniProt) |
|---|---|
| CCK-A (CCK1) | Stimulates amylase release from the pancreas; CCK's gallbladder and pancreatic actions |
| CCK-B (CCK2) | Stimulates gastric acid secretion — the same receptor gastrin uses |
That shared receptor has a structural reason. Lining up the two UniProt sequences, CCK and gastrin end in the same five amino acids, G-W-M-D-F-NH2. The rest of each molecule differs, and each has its own gene.
UniProt is candid about the brain: CCK's "function in the brain is not clear."
Sincalide: the approved eight-amino-acid copy
No product contains whole cholecystokinin. What is approved is its tip. The Kinevac label describes sincalide as "a synthetically-prepared C-terminal octapeptide of cholecystokinin" — the same eight residues as CCK-8, sulfated tyrosine included.
| Labelled use (Kinevac) | What it does |
|---|---|
| Gallbladder imaging or bile sampling | Makes the gallbladder contract; a sample of concentrated bile can be collected by duodenal aspiration |
| Pancreatic function testing, with secretin | Increases pancreatic secretion volume and enzyme output for duodenal analysis |
| Small-bowel barium studies | Speeds the barium meal, reducing fluoroscopy time and radiation |
The label's pharmacodynamics: after an intravenous bolus of 0.02 mcg/kg, maximal gallbladder contraction occurred in 5 to 15 minutes. The labelled doses are 0.02 mcg/kg by injection over 30–60 seconds, or an infusion of 0.12 mcg/kg over 50 minutes to reduce stomach effects — reported here for reference; the dose for any test is set by the team performing it.
Safety (sincalide label)
- Allergic reactions, including anaphylaxis; the product contains sodium metabisulfite.
- Gallstones: contraction of a gallbladder containing small stones could move them into the cystic or common bile duct.
- Stomach effects with fast injection: transient nausea, vomiting, abdominal pain or cramping, dizziness or flushing. Abdominal discomfort or pain and nausea are the most frequent reactions (20% or more).
- Preterm labour or spontaneous abortion is listed among the label's warnings.
What it is not
No CCK product is approved for appetite or weight. CCK's place in satiety appears in the research literature, but the opened records — UniProt and the sincalide label — describe digestive roles and an unclear brain role, nothing that supports a treatment claim.
Where it stands
- Made by the body; not a product in its own right.
- Sincalide approved since 1976-07-21 (Kinevac, Bracco, NDA 017697); a second sincalide (Maia, NDA 210850) approved 2022-11-22; both listed as prescription intravenous products (Drugs@FDA, 2026-10-11).
- Research record: PubMed indexes 20,357 records, 583 tagged as randomised trials (2026-10-11).
Related reading
CCK's closest relative is gastrin, the stomach's acid hormone, and sincalide is often used with secretin for pancreatic testing. Somatostatin suppresses several of the gut's hormones, gastrin and secretin among them.