Page data last changed: . Registry refreshes and identity assessments are separate from scientific content review.
A classic gut–brain peptide — and one of the most abundant neuropeptides in the CNS.
Also known as: CCK · CCK-8 · pancreozymin
Part of the Metabolic & GLP-1 peptides cluster
Overview
Cholecystokinin (CCK) is a peptide hormone and neurotransmitter released from intestinal I-cells and also produced widely in the brain. It triggers gallbladder contraction and pancreatic enzyme secretion after fatty meals and signals satiety, making it a foundational gut–brain peptide.
Source & context
Biological / chemical source: Intestinal I-cells and central nervous system neurons
Primary research or clinical context: Endogenous peptide; the CCK-8 fragment is used in research and imaging contexts
A family of active fragments
CCK is processed from a single precursor into several C-terminally amidated forms of different lengths — CCK-58, CCK-33, CCK-22 and the widely studied CCK-8. A sulfated tyrosine near the C-terminus is critical for full activity at the CCK-A receptor, a nice example of how post-translational modification tunes potency.
Gut and brain roles
In the gut, CCK coordinates digestion of fat and protein by stimulating bile release and pancreatic enzymes. In the brain it is one of the most abundant neuropeptides and is studied in satiety, anxiety and reward pathways. This page describes that physiology for educational purposes only.
Sequence of the selected reference form
Sequence backbone for the reference form: Human sulfated cholecystokinin-8 (CCK-8S), C-terminal amide. Termini, stereochemistry and modifications are described below.
Structure & chemistry
Molecular identity & reference confidence
Source-supported reference
Choose the eight-residue sulfated, amidated human CCK reference form. The reviewed precursor explicitly identifies CCK-8, sulfotyrosine97 and phenylalanine amide103; the PubChem molecular graph independently contains Tyr O-sulfate and terminal amide. Other CCK lengths remain distinct forms.
- Molecular form
- Human sulfated cholecystokinin-8 (CCK-8S), C-terminal amide
- Species
- Homo sapiens
- Termini (N / C)
- Free alpha-amino group of L-aspartate / L-phenylalanine carboxamide (-CONH2)
Average reference mass · Molecular identity assessment: 2026-10-05
Reference policy updated: 2026-10-05
- PubChem PUG molecular properties and explicit molecular graph · 2026-10-05
- PubChem PUG stereochemistry and normalized structure identity · 2026-10-05
- Reviewed UniProt molecular sequence and processed-chain annotations · 2026-10-05
- Molecular cloning of the human cholecystokinin gene by use of a synthetic probe containing deoxyinosine. · 2026-10-05
Asp-Tyr(O-sulfate)-Met-Gly-Trp-Met-Asp-Phe-NH2
- Molecular formula
- C49H62N10O16S3
- Average reference mass
- ≈ 1,143.3
- Backbone
- Human sulfated cholecystokinin-8 (CCK-8S), C-terminal amide
- C-terminus
- L-phenylalanine carboxamide (-CONH2)
- PubChem CID: 9833444
Chemistry values: curated profile, PubChem.
Clinical development snapshot
ClinicalTrials.gov lists 31 registered studies with “Cholecystokinin” as an intervention (snapshot 2026-09-06). A registry footprint is not evidence of efficacy or approval.
| NCT | Title | Phase | Status | Updated |
|---|---|---|---|---|
| NCT05551858 | Role of a CCK Receptor Antagonist Proglumide in Management of Chronic Pancreatitis | Phase 2 | active not recruiting | 2026-08-05 |
| NCT05827055 | Proglumide and Chemotherapy for Metastatic Pancreatic Cancer | Phase 2 | active not recruiting | 2026-06-10 |
| NCT07138716 | Research on the Application of 68Ga-DOTA-CCK-FS PET/CT in MTC | Not applicable | recruiting | 2025-08-24 |
| NCT07019519 | POTS-FLOW: Interplay Between Gut Hormones and Autonomic Postprandial Blood Flow Regulation in Patients With PO | Not applicable | recruiting | 2025-06-13 |
| NCT03904576 | A Study in Healthy Men to Test Whether BI 1358894 Reduces Druginduced Panic Symptoms | Phase 1 | completed | 2025-03-19 |
| NCT04651868 | The Effect of Exogenous Glucagon-like Peptide 2 on Cholecystokinin-induced Gallbladder Emptying | Not applicable | completed | 2024-12-09 |
Cholecystokinin — reconstitution calculator
Enter how much peptide is in the vial and how much diluent (e.g. bacteriostatic water) is added. The tool returns the resulting solution concentration — and, for any amount you type, the volume it corresponds to. This is educational arithmetic, not a dosing recommendation.
Reference form: Human sulfated cholecystokinin-8 (CCK-8S), C-terminal amideAverage reference mass: 1,143.3 Da
Enter an amount to see the volume it corresponds to.
Educational concentration mathematics only. This tool does not recommend a dose, amount, or protocol, and nothing here is medical advice. Many peptides are not authorized by Health Canada for human use — see our reconstitution and bacteriostatic-water guides for context.
Change log
Dated observations from the data pipeline (registry flags, trial footprints, identifiers) and editorial reviews of this profile.
- ChemistryPubChem formula updated to C49H62N10O16S3.
FAQ about Cholecystokinin
What is Cholecystokinin?+
Cholecystokinin (CCK) is a peptide hormone and neurotransmitter released from intestinal I-cells and also produced widely in the brain. It triggers gallbladder contraction and pancreatic enzyme secretion after fatty meals and signals satiety, making it a foundational gut–brain peptide.
What Canadian product status is recorded for Cholecystokinin?+
Canadian product status for Cholecystokinin has not been verified in this profile. No verified record here does not mean no authorization exists. Status depends on the product, formulation and use; consult Health Canada's product records.
What is the length of the selected reference form for Cholecystokinin?+
The selected reference form (Human sulfated cholecystokinin-8 (CCK-8S), C-terminal amide) has 8 residues or residue-derived units in its backbone. Other forms in this family may have a different length.
Related peptides
References & further reading
- 1.Iwata et al. (1999). [Cholecystokinin.pancreozymin (CCK-PZ)]. Nihon Rinsho
- 2.Vázquez-León et al. (2018). Differential effects of cholecystokinin (CCK-8) microinjection into the ventrolateral and dorsolateral periaqueductal gray on anxiety models in Wistar rats. Horm Behav
- 3.Han et al. (1986). Cholecystokinin octapeptide (CCK-8): antagonism to electroacupuncture analgesia and a possible role in electroacupuncture tolerance. Pain
- 4.Smith (1984). The therapeutic potential of cholecystokinin. Int J Obes
- 5.Melton et al. (1992). Cholecystokinin (CCK-8) affects gastric pressure and ratings of hunger and fullness in women. Am J Physiol
- 6.Prospéro-García et al. (1987). Cerebroventricular infusion of cholecystokinin (CCK-8) restores REM sleep in parachlorophenylalanine (PCPA)-pretreated cats. Neurosci Lett
- 7.Han (1995). Cholecystokinin octapeptide (CCK-8): a negative feedback control mechanism for opioid analgesia. Prog Brain Res
- 8.Zhou et al. (1989). [Cholecystokinin octopeptide (CCk-8): opioid or antiopioid activity]. Sheng Li Ke Xue Jin Zhan
- 9.UniProt — CCK, Cholecystokinin, human (P06307)
- 10.Wikipedia — Cholecystokinin