Urocortin-2
Also known as: UCN2, Urocortin II, stresscopin-related peptide, SRP
Endogenous neuropeptide; member of the corticotropin-releasing factor (CRF) family; selective agonist of CRF receptor type 2 (CRHR2)
What it is
Researchers studying heart failure, stress physiology, and metabolic disease have focused on urocortin-2 for its ability to widen blood vessels, improve cardiac output, and modulate the stress hormone axis. Interest spans cardiology, neuroscience, and obesity research, with completed human trials exploring its use as an intravenous agent in heart failure patients.
The scientific side
urocortin-2 (UCN2) is an endogenous peptide that belongs to the corticotropin-releasing factor (CRF) family and acts as a selective agonist at CRF receptor type 2 (CRHR2). CRHR2 is expressed broadly across tissues including cardiomyocytes, neurons, skeletal muscle, skin dendritic cells, and spinal cord glia. Upon binding CRHR2, UCN2 activates the cAMP-PKA signaling pathway, leading to downstream phosphorylation of CREB and upregulation of pro-survival proteins such as Bcl-2, while suppressing pro-apoptotic and pro-inflammatory mediators including NF-κB, RhoA, and Bax. In the cardiovascular system, UCN2 infusion produces vasodilation with a reduction in systemic blood pressure and a compensatory increase in heart rate, effects that have been reproduced in both humans and minipig preclinical models. In heart failure animal studies, chronic intraperitoneal UCN2 administration improved survival in a dose-dependent manner and upregulated cardiac SERCA2 and CRF2 receptor expression without worsening anxiety-like behavior. In the central nervous system, UCN2 expressed in the paraventricular nucleus (PVN) of the hypothalamus plays a key role in the stress response: UCN2-positive PVN neurons are activated by metabolic stressors such as hypoglycemia and by brainstem norepinephrine inputs, and central UCN2 injection rapidly inhibits pulsatile luteinizing hormone secretion via direct suppression of arcuate kisspeptin neurons. UCN2 also modulates energy balance by suppressing food intake through hypothalamic CRH-R2 signaling and influencing circadian clock gene expression including Bmal1. In the skin, UCN2 produced by CD141+ dendritic cells under vitamin D3 and UVB stimulation promotes regulatory T-cell generation and reduces cutaneous inflammation. In spinal cord injury models, UCN2 administration reduced neuronal apoptosis, shifted astrocytes from a neurotoxic A1 to a regenerative A2 phenotype, suppressed microglial activation, and enhanced axonal regeneration through the cAMP-PKA pathway. Circulating UCN2 concentrations are elevated in heart failure and hypertension patients compared to controls, and show an inverse association with serum chloride levels in large heart failure cohorts, suggesting a role in electrolyte homeostasis.
Class: Endogenous neuropeptide; member of the corticotropin-releasing factor (CRF) family; selective agonist of CRF receptor type 2 (CRHR2)
Administration & storage
- Administration
- Intravenous infusion (human clinical trialsheart failure)Intraperitoneal injection (rodent studies — heart failurespinal cord injury)Intracerebroventricular injection (rodent studies — metabolic/thermic responses)Intranasal administration (rodent studies — PTSD model)
- Storage
- No storage conditions for UCN2 preparations are described in the fetched abstracts.
Legal & regulatory status
Not approved for any therapeutic indication. Used only as an investigational agent in clinical research settings (e.g., NCT01599728, NCT01296607). No IND or NDA identified in the fetched literature.
Not explicitly listed in the fetched literature. As an endogenous peptide hormone acting on cardiovascular and metabolic pathways, its status under relevant WADA categories cannot be confirmed from the available…
No approved therapeutic indication identified in the fetched abstracts or trial records.
What it's studied for
- Heart failure — hemodynamic support and biomarker Phase 2 human trials (completed) + animal studies
- Hypertension — elevated serum levels and potential pathophysiological role Observational human study
- Spinal cord injury — neuroprotection and motor function recovery Preclinical (rodent models)
- Post-traumatic stress disorder (PTSD) — modulation of stress-immune-brain axis Preclinical (rodent model)
- Metabolic regulation — food intake suppression, energy balance, and obesity Preclinical (rodent models) + mechanistic cell studies
- Skin immunity — regulation of cutaneous inflammation via CD141+ dendritic cells Preclinical (humanized mouse model) + ex vivo human skin
- Parkinson's disease — stress neuropeptide circuit dysregulation Preclinical (rodent model)
- Vascular calcification — endogenous promoter via Wnt/β-catenin signaling Preclinical (in vitro cell model)
Safety signals
- Hypotension and reflex tachycardia
- Intermittent hypoxia-associated hypertension — CRHR2 in nucleus of solitary tract may exacerbate blood pressure elevation
- Vascular calcification promotion via Wnt/β-catenin pathway
- Suppression of luteinizing hormone pulses and LH surge — potential reproductive endocrine disruption
- Age-related exaggeration of hyperthermia and hypermetabolism
- No anxiety- or stress-like behavioral worsening at therapeutic cardiac doses in rats
- Elevated circulating UCN2 in disease states (hypertension, heart failure) — directionality of causality unclear
All studies (2)
Frequently asked
Has urocortin-2 been tested in humans?
Yes. Multiple completed clinical trials administered intravenous UCN2 to healthy volunteers and heart failure patients (e.g., NCT01599728, NCT01049542, NCT01096693, NCT01296607, NCT01096706), primarily to assess vasodilatory effects on forearm blood flow and cardiac hemodynamics. A separate trial (NCT05115552) compared UCN2 to BNP as a biomarker in acute decompensated heart failure. These trials were conducted in controlled research settings and UCN2 is not approved as a therapeutic drug.
What does urocortin-2 do to the heart?
Based on published research, UCN2 binds CRHR2 receptors on cardiomyocytes and vascular smooth muscle. IV infusion produces vasodilation and blood pressure reduction with a compensatory rise in heart rate. In rat heart failure models, chronic UCN2 treatment improved survival in a dose-dependent manner and upregulated the calcium-handling protein SERCA2. Circulating UCN2 concentrations are elevated in human heart failure and hypertension, where it may act as a compensatory response. Whether exogenous UCN2 provides net benefit in human cardiac disease has not been established in definitive trials.
Can urocortin-2 affect reproductive hormones?
Preclinical data in mice show that central injection of UCN2 rapidly suppresses pulsatile and surge LH secretion by acting directly on kisspeptin neurons through CRHR2. UCN2-positive neurons in the paraventricular nucleus are activated by metabolic stressors such as hypoglycemia, suggesting this pathway may mediate stress-induced suppression of reproductive function. No human reproductive endocrinology trials involving UCN2 were identified in the available literature.
Is urocortin-2 the same as urocortin?
No. Urocortin-2 is one of three distinct urocortin peptides (UCN1, UCN2, UCN3). Unlike urocortin-1, which binds both CRHR1 and CRHR2, UCN2 is selective for CRHR2. CRHR2 has distinct tissue distribution and functional roles compared to CRHR1, with UCN2 playing a prominent role in cardiovascular regulation, energy balance, and stress recovery rather than the anxiogenic stress initiation associated with CRHR1 signaling.
What evidence supports urocortin-2 for spinal cord injury?
Evidence is currently limited to preclinical rodent models. Two published studies in rats with T10 spinal cord transection showed that UCN2 administration reduced neuronal apoptosis, suppressed neuroinflammation, shifted astrocytes from a neurotoxic to a regenerative phenotype, and improved hindlimb motor function via cAMP-PKA signaling. A related study found that electroacupuncture also improved motor outcomes through UCN2-mediated pathways. No human spinal cord injury trials involving UCN2 have been reported in the available literature.