Cholecystokinin-8 vs Met-enkephalin
Head-to-head comparison of Cholecystokinin-8 (Cholecystokinin (sulfated C-terminal octapeptide, CCK-8)) and Met-enkephalin (Tyr-Gly-Gly-Phe-Met) — benefits, dosing, side effects, research data, and where to buy.
Research Score
| Property | Cholecystokinin-8 | Met-enkephalin |
|---|---|---|
| Category | Endocrine Peptides | Pain Management |
| Full Name | Cholecystokinin (sulfated C-terminal octapeptide, CCK-8) | Tyr-Gly-Gly-Phe-Met |
| Molecular Weight | 1143.2 Da | 573.67 Da |
| Half-Life | 1-2 min | 1-5 minutes in plasma |
| Amino Acids | DY(SO3H)MGWMDF-NH2 | 5 |
| Typical Dose | physiologic low-picomolar-nanomolar range|research-dependent | 0.1-5 ug per animal |
| Route | endogenous secretion|research IV/SC | Intrathecal / intracerebroventricular |
| Purity | ≥98% | ≥98% |
| Studies Count | 97 | 1200 |
| Research Status | Endogenous | Pre-clinical |
Cholecystokinin-8 Benefits
- ✓gallbladder contraction
- ✓pancreatic enzyme release
- ✓satiety signaling
Met-enkephalin Benefits
- ✓endogenous opioid signaling
- ✓analgesic reference ligand
- ✓spinal antinociception
- ✓neurochemical pain-pathway probe
Cholecystokinin-8 Dosing
physiologic secretion|research-dependent
Met-enkephalin Dosing
Intrathecal 0.1-5 ug per animal|Intracerebroventricular 0.1-2 ug per animal|In vitro 1-100 nM
Cholecystokinin-8 Side Effects
- ⚠abdominal cramping
- ⚠nausea
- ⚠biliary contraction
Met-enkephalin Side Effects
- ⚠sedation at higher exposure
- ⚠constipation-like opioid effects
- ⚠rapid enzymatic degradation
Research Overview
Cholecystokinin-8
CCK-8 is a canonical gut hormone fragment with extensive documentation in digestive physiology and appetite control. Sulfation of the tyrosine residue is important for high-affinity receptor activity.
Met-enkephalin
Met-enkephalin has been extensively used in receptor pharmacology and nociception studies to map mu and delta opioid biology. The main limitation in translational work is very short half-life from peptidase cleavage and poor systemic stability.
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