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| 1mg |
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| 10mg |
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| Targets |
Urocortin III is a high‑affinity, selective agonist for the type‑2 corticotropin‑releasing factor receptor (CRF‑R2). It does not bind significantly to the CRF‑R1 receptor. CRF‑R2 is a class B GPCR that activates the adenylate cyclase‑cAMP‑PKA pathway. The receptor is expressed in the brain (e.g., lateral septum, amygdala) and in peripheral tissues, including the heart, skeletal muscle, and gastrointestinal tract.
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| ln Vitro |
In vitro, mouse urocortin III stimulates cAMP accumulation in cells expressing recombinant mouse or human CRF‑R2 with an EC₅0 in the low nanomolar range (1‑5 nM). In contrast, it has no effect on CRF‑R1 at concentrations up to 1000 nM, demonstrating >100‑fold selectivity. The peptide also increases neurite outgrowth in cultured cortical neurons in a CRF‑R2‑dependent manner.
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| ln Vivo |
In mice, intracerebroventricular (i.c.v.) injection of urocortin III (0.1‑1 ug) produces anxiogenic‑like effects in the elevated plus maze and open field tests, indicating activation of stress‑related behaviors. When administered peripherally (i.p., 30‑100 ug/kg), urocortin III reduces food intake, increases energy expenditure, and improves glucose tolerance in diet‑induced obese mice, consistent with CRF‑R2‑mediated metabolic effects.
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| Enzyme Assay |
Receptor binding is assessed using membrane preparations from HEK‑293 cells stably expressing mouse CRF‑R2. Membranes (20‑50 ug) are incubated with [¹2⁵I]‑sauvagine (a CRF‑R1/R2 agonist) (0.1 nM) and increasing concentrations of unlabeled mouse urocortin III (0.001‑1000 nM) in binding buffer (50 mM Tris‑HCl, pH 7.4, 5 mM MgCl2, 0.1% BSA). After 60 minutes at 25degC, bound radioactivity is separated by filtration. Non‑specific binding is defined with 1 uM unlabeled urocortin III. The Kᵢ is determined using the Cheng‑Prusoff equation.
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| Cell Assay |
Cells (e.g., HEK‑293) expressing CRF‑R2 are seeded in 96‑well plates and treated with mouse urocortin III (0.01‑1000 nM) for 15‑30 minutes. The reaction is stopped by removing the medium and adding cell lysis buffer. Intracellular cAMP levels are then measured using a competitive ELISA or a homogenous time‑resolved fluorescence (HTRF) cAMP kit. The EC₅0 is derived by fitting the data to a four‑parameter logistic curve. For neurite outgrowth studies, primary mouse cortical neurons are treated with urocortin III (10‑100 nM) for 48 hours.
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| Animal Protocol |
Adult male C57BL/6 mice (8‑10 weeks old) are anesthetized and placed in a stereotaxic apparatus for i.c.v. injection (coordinates: 0.3 mm posterior, 1.0 mm lateral, 2.5 mm ventral from bregma). Mouse urocortin III (0.1‑1 ug in 2 uL saline) or vehicle is injected over 2 minutes. Behavioral tests (elevated plus maze, open field) are performed 15‑30 minutes after injection. Alternatively, for metabolic studies, the peptide (30‑100 ug/kg) is injected intraperitoneally 1 hour before measuring food intake or performing glucose tolerance tests.
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| ADME/Pharmacokinetics |
As a 38‑amino acid peptide, mouse urocortin III is rapidly degraded in plasma (half‑life <10 minutes). The TFA salt does not alter this. When administered i.c.v., the peptide stays in the cerebrospinal fluid longer (half‑life 30‑60 minutes). The peptide does not cross the blood‑brain barrier effectively. For peripheral effects, high doses are required, and the peptide acts directly on peripheral CRF‑R2 receptors.
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| Toxicity/Toxicokinetics |
In acute studies, mouse urocortin III (up to 100 ug/kg, i.p.) is well‑tolerated, with no overt signs of toxicity. At very high i.c.v. doses (≥2 ug), mice may display excessive grooming and reduced locomotor activity. Chronic peripheral administration (30 ug/kg daily for 14 days) has been reported to be safe, with no significant changes in liver or kidney function markers. No formal toxicology studies have been published.
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| References |
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| Additional Infomation |
Urocortin III is a research tool for studying the CRF‑R2 pathway in stress, anxiety, metabolism, and cardiovascular function. The TFA salt is the standard research formulation. The peptide is not approved for human therapeutic use. In contrast to CRF and urocortin I, which activate both CRF‑R1 and CRF‑R2, urocortin III's selectivity for CRF‑R2 allows dissection of the roles of the two receptor subtypes in complex physiological and behavioral responses.
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| Molecular Formula |
C188H313N52F3O54S2
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| Molecular Weight |
4286.99
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| Related CAS # |
Urocortin III, mouse;357952-10-4
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| Appearance |
White to off-white solid powder
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
H2O :~25 mg/mL (~5.83 mM)
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| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 0.2333 mL | 1.1663 mL | 2.3326 mL | |
| 5 mM | 0.0467 mL | 0.2333 mL | 0.4665 mL | |
| 10 mM | 0.0233 mL | 0.1166 mL | 0.2333 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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