Urocortin
Also known as: UCN, UCN1, Urocortin I, Urocortin 1, Urocortin-1, stresscopin-related peptide (UCN2), stresscopin (UCN3), Urocortin 2, Urocortin 3
Endogenous neuropeptide — corticotropin-releasing factor (CRF) family; CRF receptor ligand
What it is
Urocortin is a natural signaling peptide your body makes to regulate the stress response, heart function, and metabolism. It has shown genuine promise in heart failure research, where early clinical trials demonstrated it can lower blood pressure and improve heart output — but it has not reached approval for any indication.
The scientific side
urocortin (UCN) refers to a family of endogenous 40-amino-acid neuropeptides — UCN1, UCN2 (stresscopin-related peptide), and UCN3 (stresscopin) — that are members of the corticotropin-releasing factor (CRF) superfamily and act as ligands for two G protein-coupled receptors, CRF receptor type 1 (CRFR1) and CRF receptor type 2 (CRFR2). UCN1 binds both CRFR1 and CRFR2 with high affinity, while UCN2 and UCN3 are selective for CRFR2, which is the primary receptor mediating cardiovascular and metabolic effects. Receptor binding activates adenylyl cyclase via Gs coupling, elevating intracellular cyclic AMP (cAMP) and triggering downstream protein kinase A (PKA) signaling. At high concentrations of UCN2, CRFR2 also recruits Gi and beta-arrestin, leading to receptor internalization and desensitization, which mechanistically explains why chronic UCN2 exposure can improve insulin sensitivity whereas acute dosing worsens it. In the cardiovascular system, CRFR2 activation in cardiac and vascular tissue produces positive inotropy, coronary vasodilation with increased coronary blood flow, peripheral vasodilation lowering systemic vascular resistance, and direct cardioprotection against ischemia-reperfusion injury through activation of the reperfusion injury salvage kinase (RISK) pathway involving PI3K, Akt, and ERK1/2, as well as mitochondrial KATP channel opening that reduces mitochondrial permeability transition pore opening and cardiomyocyte apoptosis (PMIDs: 19406492, 34829997). UCN2- and UCN3-mediated vasodilation in humans is partially endothelium-dependent, involving nitric oxide synthase and cytochrome P450 metabolites of arachidonic acid, with a characteristically slow onset and offset of action and no tachyphylaxis observed in clinical pharmacological studies. In the neuroendocrine axis, UCN1 activates the hypothalamic-pituitary-adrenal (HPA) axis via CRFR1 in the pituitary, stimulating ACTH and cortisol release; UCN2 in the paraventricular nucleus suppresses luteinizing hormone secretion by directly inhibiting kisspeptin neurons via CRFR2, providing a mechanistic link between physiological stress and reproductive suppression. In skeletal muscle, urocortins regulate glucose uptake, muscle hypertrophy, and metabolic flexibility via CRFR2-cAMP-PKA pathways, making them emerging targets for obesity and sarcopenia. The UCN3/CRFR2 axis also regulates pancreatic beta-cell insulin secretion and modulates somatostatin signaling, positioning UCN3 as a regulator of glucose homeostasis (PMIDs: 35738909, 37402735).
Class: Endogenous neuropeptide — corticotropin-releasing factor (CRF) family; CRF receptor ligand
Administration & storage
- Administration
- Intra-arterial infusion into the brachial artery using forearm venous occlusion plethysmography technique (human pharmacology studies; PMIDs: 2352543234378854)Intravenous infusion for systemic hemodynamic assessment in heart failure patients (clinical trials; PMID: 34378854)No subcutaneous or intramuscular administration has been reported in human clinical studies
- Storage
- No commercial formulation; storage conditions are trial-specific. Peptides of this class are generally stored lyophilized at -20°C or lower and are reconstituted immediately before use under sterile conditions.
- Cautions
- All human administration has been investigational only; urocortin is not a pharmaceutical product approved for clinical use in any country.,Cardiovascular monitoring required: UCN2 and UCN3 produce significant vasodilation and blood pressure lowering (mean arterial pressure reduction ~9 mmHg) and mild tachycardia in HF patients; hemodynamic monitoring is essential.,Acute insulin resistance has been observed with single-dose UCN2 in preclinical models; metabolic monitoring may be warranted in human studies.,Hypothalamic-pituitary-adrenal axis activation via CRFR1 (UCN1) could elevate cortisol; neuroendocrine monitoring relevant in research contexts (PMIDs: 22548056, 39523064).,No long-term safety data exist in humans. Duration of all reported human studies has been limited to single sessions or short-course administration.
Legal & regulatory status
Urocortin (UCN1, UCN2, UCN3) is not FDA-approved for any indication. All human studies to date have been investigational. UCN1 and UCN2 have been evaluated in Phase I/II clinical trials for heart failure and…
Urocortin peptides are not explicitly named on the WADA Prohibited List. However, as endogenous peptides with cardiovascular (positive inotropic, vasodilatory) and metabolic effects, they could fall under broad…
Urocortin (any isoform) is not approved by Health Canada for any therapeutic indication. No Drug Identification Number (DIN) exists for UCN1, UCN2, or UCN3. All reported human use has been within controlled clinical…
What it's studied for
- Chronic heart failure with reduced ejection fraction — blood pressure and hemodynamic improvement Phase II clinical trial / systematic review and meta-analysis
- Cardioprotection against ischemia-reperfusion injury — pre- and post-conditioning Preclinical / Translational (pilot clinical data)
- Urocortin 1 and 2 as biomarkers for heart failure severity and diagnosis Observational clinical studies
- Peripheral vascular effects and forearm vasodilation in healthy volunteers and heart failure patients Phase I/II human pharmacology study
- Metabolic effects — insulin sensitivity, skeletal muscle glucose uptake, and lean mass preservation Preclinical / Early translational
- Stress-response neuroendocrine modulation — reproductive axis suppression and HPA axis regulation Preclinical / Basic science with human implications
Safety signals
- Hypotension and hemodynamic instability from vasodilation
- Tachycardia and increased heart rate
- Acute insulin resistance with single-dose UCN2 exposure
- HPA axis activation and elevated cortisol secretion via CRFR1 (UCN1)
- Reproductive axis suppression — LH pulse inhibition via UCN2-CRFR2 signaling
- Lack of long-term human safety data — all studies are short-duration investigational trials
Contraindications
About these dose ranges
Dose ranges below reflect commonly reported community protocols. Where published research cites a specific dose, the PMID is linked. Doses without citations are not clinical recommendations — they reflect what practitioners and researchers commonly report using.
Community-reported dosing
| Route | Dose | Frequency / Duration | Population / context | Source tier |
|---|---|---|---|---|
| Unspecified | Infusion rates ranging from 3.6 to 120 pmol/min intra-arterially in forearm pharmacology studies; systemic infusion doses in clinical HF trials varied across published studies (exact systemic doses not standardized across included meta-analytic studies) | — | Adults with chronic heart failure with reduced ejection fraction — intravenous infusion (UCN2) | Research |
| Unspecified | UCN2: 3.6, 12, 36, and 120 pmol/min intra-arterially; UCN3: 1.2, 3.6, 12, and 36 nmol/min intra-arterially | — | Healthy male volunteers — forearm pharmacology (UCN2 and UCN3) | Research |
| intra-arterial or intravenous infusion under clinical trial conditions | UCN2 intra-arterial infusion: 3.6–120 pmol/min (forearm pharmacology); systemic infusion: variable across trials | single-session to short-course investigational administration | adult patients with chronic heart failure with reduced ejection fraction in Phase I/II clinical research settings |