| Size | Price | Stock | Qty |
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| 5mg |
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| Other Sizes |
| Targets |
Growth hormone-releasing hormone receptor (GHRH-R). Human GRF (1-44) amide TFA is an endogenous agonist of the GHRH receptor (GHRH-R), a class B G protein-coupled receptor (GPCR) expressed on somatotroph cells of the anterior pituitary. Binding of GRF to GHRH-R activates the Gs protein, leading to increased intracellular cAMP and activation of PKA. This signaling cascade stimulates the transcription of the GH gene and the exocytosis of pre-formed GH secretory granules. The result is a rapid and dose-dependent increase in plasma GH levels. GRF is the primary physiological regulator of pulsatile GH secretion. The 44-amino acid amidated form is the major isoform in humans. The TFA salt does not alter receptor binding or biological activity.
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| ln Vitro |
The class II B GPCR family, to which the Gs-adenylate cyclase-cAMP signaling pathway is mostly coupled, includes the GHRHR. GHRH, secretin, glucagon-like peptides, gastric-inhibitory peptide (GIP), pituitary adenylate cyclase-activating peptide, corticotropin-releasing hormone, vasoactive intestinal peptide, parathyroid hormone, and calcitonin-related peptides are among the peptide hormones that activate class II GPCRs[1]. Growth hormone synthesis and secretion from the pituitary somatotropes are directly stimulated by GHRH, which is expressed in the arcuate nucleus of the hypothalamus and released into the portal vasculature by activating the appropriate GHRH receptors[1].
In vitro, Human GRF (1-44) amide TFA stimulates GH release from primary rat or human pituitary cells in a concentration-dependent manner. Primary anterior pituitary cells are cultured for 3-5 days, then treated with GRF (0.01-1000 nM) for 15-60 minutes. GH released into the medium is measured by ELISA or radioimmunoassay (RIA). The EC50 is typically in the low nM range (0.1-5 nM). The peptide also stimulates cAMP accumulation in GHRH-R-expressing cell lines (e.g., HEK293 transfected with GHRH-R) with similar potency. GRF (1-44) amide is fully active and more stable than shorter fragments (e.g., GRF(1-29)). It does not induce cytotoxicity in pituitary cells at concentrations up to 1 uM. The peptide is also used to establish GH secretion dynamics in perifusion systems. |
| ln Vivo |
In vivo, Human GRF (1-44) amide TFA potently increases plasma GH levels in animals and humans. In male Sprague-Dawley rats, intravenous (i.v.) or subcutaneous (s.c.) administration of GRF at doses of 1-100 ug/kg produces a rapid peak in serum GH (within 5-15 minutes), returning to baseline by 30-60 minutes. The effect is dose-dependent and specific, as it is blocked by GHRH antagonists. In GH-deficient animal models (e.g., dwarf rats), GRF partially restores GH pulses. In humans, synthetic GRF (somatorelin) is used as a diagnostic test to assess pituitary GH reserve. The 1-44 amide is more potent and longer-acting than the 1-29 fragment. The TFA salt formulation is suitable for in vivo injection after neutralization. It is not used for chronic therapy due to short half-life; that role is filled by GH-releasing peptide analogs or GH itself.
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| Enzyme Assay |
For a non-cellular GHRH-R binding assay, surface plasmon resonance (SPR) or radioligand binding can be used. For SPR: Immobilize recombinant human GHRH-R extracellular domain or full-length receptor (reconstituted in nanodiscs) on a sensor chip. Dissolve Human GRF (1-44) amide TFA in running buffer (10 mM HEPES pH 7.4, 150 mM NaCl, 3 mM EDTA, 0.005% P20, 1 mM DTT, 0.1% BSA). Flow concentrations from 0.1-1000 nM over the chip. Calculate KD (typically low nM). For radioligand binding: Use membranes from GHRH-R-transfected CHO cells. Incubate membranes (20-50 ug protein) with 0.05-0.1 nM 125I-GRF and varying concentrations of unlabeled GRF (0.001-1000 nM) in binding buffer for 60-90 min at 25degC. Filter through GF/B presoaked in 0.3% PEI, wash, and count. IC50 is determined, and Ki calculated (usually 0.5-5 nM). For a functional cell-free assay, use membrane adenylyl cyclase activity: incubate membranes with GRF (0.1-1000 nM) and assay cAMP production by ELISA.
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| Cell Assay |
For cellular assays, use primary rat pituitary cells or the GH3 cell line (which expresses endogenous GHRH-R). Seed cells in 24-well plates (2×10^5 cells/well) in DMEM with 10% FBS for 3 days. Wash and incubate in serum-free medium for 24 hours. Then add Human GRF (1-44) amide TFA (0.01-1000 nM) for 15-30 min at 37degC. Collect supernatants and measure GH by ELISA (rat/mouse GH). The EC50 is typically 0.1-1 nM. For cAMP measurement, treat cells with GRF for 15 min in the presence of 0.5 mM IBMX, lyse, and measure cAMP using an HTRF or ELISA kit. The EC50 for cAMP is similar. For receptor internalization studies, treat cells with FITC-labeled GRF and observe by confocal microscopy. The TFA salt is water-soluble; prepare 1 mM stock in PBS (pH 7.4) and store at -20degC. Avoid repeated freeze-thaw. Control: vehicle (PBS). Positive control: GRF(1-29) or forskolin.
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| Animal Protocol |
For in vivo studies, use male Sprague-Dawley rats (200-250 g). Anesthetize with isoflurane. Insert a catheter into the jugular vein for blood sampling. Dissolve Human GRF (1-44) amide TFA in sterile saline (0.9% NaCl), adjust pH to 7.0-7.5. Administer as an intravenous bolus (via tail vein or jugular) at doses of 0.1, 1, 10, 100 ug/kg (volume 1-2 mL/kg). Collect blood samples at -5 (pre-dose), 2, 5, 10, 15, 30, 60, 90, 120 min post-dose. Separate plasma by centrifugation. Measure GH levels using a rat GH ELISA kit. The peak GH response should occur at 5-15 min. For subcutaneous administration, inject into the scruff of the neck. The effect is similar but with slightly delayed peak. The compound is well-tolerated; repeated dosing may lead to desensitization. For diagnostic testing in humans, somatorelin is given as an i.v. bolus (1 ug/kg). For research use only; not for human administration without regulatory approval.
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| ADME/Pharmacokinetics |
Human GRF (1-44) amide TFA has a very short plasma half-life in humans and rodents (t1/2 ≈ 5-15 minutes) due to rapid enzymatic degradation (primarily by dipeptidyl peptidase-4, DPP-4, and neutral endopeptidase 24.11). The peptide is cleared by the kidneys and metabolized in liver and plasma. Following intravenous injection in rats, the elimination half-life is approximately 6-10 minutes. The volume of distribution (Vd) is small (≈0.2 L/kg), indicating limited tissue distribution. Clearance (CL) is high (≈20-40 mL/min/kg). Bioavailability after subcutaneous injection is moderate (30-50%). The TFA salt does not alter PK. For PK studies, administer GRF (10 ug/kg, i.v.) to rats, collect blood at 0, 2, 5, 10, 15, 30, 60 min, and quantify by LC-MS/MS using a deuterated internal standard. Calculate PK parameters by non-compartmental analysis.
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| Toxicity/Toxicokinetics |
Acute toxicity of GRF is low. In rodents, the intravenous LD50 is >10 mg/kg. At suprapharmacological doses (≥1 mg/kg), transient hypotension, flushing, and mild gastrointestinal discomfort may occur due to vasodilation. No genotoxicity, carcinogenicity, or teratogenicity has been observed. In repeated-dose studies (e.g., 28 days in rats at 50-200 ug/kg/day), no significant organ toxicity is seen, though some weight gain may occur due to increased GH/IGF-1. Clinically, somatorelin is safe for diagnostic use; side effects include facial flushing, headache, nausea, and injection site reactions, which are usually mild and transient. The TFA salt is non-toxic at the amounts used. Standard laboratory safety precautions apply. It is not intended for therapeutic chronic use.
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| References | |
| Additional Infomation |
Human GRF (1-44) amide (somatorelin) is the endogenous growth hormone-releasing hormone (GHRH) produced in the hypothalamus. It is released into the hypothalamic-pituitary portal circulation and stimulates GH pulse release. The 44-amino acid amidated form (Ser-Tyr-Arg-Ile-Leu-Asn-Gln-Ala-Arg-Arg-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-Gln-Gln-Gly-Glu-Ser-Asn-Gln-Glu-Arg-Gly-Ala-Arg-Ala-Arg-Leu-NH2) is the major biologically active form. GRF(1-29) is also active but less stable. Somatorelin has been used as a diagnostic agent for GH deficiency in children and adults. It is not used for chronic treatment due to short half-life; GH-releasing peptides (e.g., sermorelin) and GH itself are used for therapy. The TFA salt is for research only. This product is not approved for human therapy; for clinical use, the acetate salt (somatorelin) is available by prescription.
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| Molecular Formula |
C217H359F3N72O68S
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| Molecular Weight |
5153.67
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| Related CAS # |
Human growth hormone-releasing factor;83930-13-6
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| Appearance |
Typically exists as solid at room temperature
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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) |
May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples
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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 | 0.1940 mL | 0.9702 mL | 1.9404 mL | |
| 5 mM | 0.0388 mL | 0.1940 mL | 0.3881 mL | |
| 10 mM | 0.0194 mL | 0.0970 mL | 0.1940 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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