| Size | Price | Stock | Qty |
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| 1mg |
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| Other Sizes |
| Targets |
Its primary target is the intestinal guanylate cyclase-C (GC-C), a receptor expressed on the apical membrane of intestinal epithelial cells. Upon activation, it increases intracellular cyclic GMP (cGMP) levels. This leads to the activation of the CFTR chloride channel and inhibition of the NHE3 sodium-hydrogen exchanger, resulting in net secretion of Cl-, HCO3-, and water, thereby regulating intestinal fluid and electrolyte homeostasis. It acts as a natriuretic and diuretic hormone.
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| ln Vitro |
In vitro, Guanylin (mouse, rat) TFA (0.1-10 uM) activates guanylate cyclase C (GC-C) in T84 human colon carcinoma cells, leading to increased cGMP production (EC₅0 of 3.4 ng/ml). cGMP levels are measured using an ELISA or radioimmunoassay (RIA). It also increases short-circuit current (Isc) in Ussing chamber experiments, indicating Cl- secretion, and inhibits the absorption of Na+ via NHE3. These effects are specific to GC-C and are blocked by the GC-C antagonist HS-142-1. Guanylin has also been shown to induce apoptosis in colon cancer cells through cross-talk between cGMP/PKG and MAPK pathways, and may play a role in carcinogenesis.
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| ln Vivo |
In vivo, guanylin acts as an intestinal paracrine hormone that regulates fluid and electrolyte secretion. In murine models, it is involved in the pathophysiology of infectious diarrhea (e.g., by enterotoxigenic E. coli heat-stable toxin, STa). Guanylin knockout mice exhibit reduced intestinal cGMP levels, impaired fluid secretion, and constipation, supporting its role in stimulating fluid secretion. Mice injected intraperitoneally (IP) or intravenously (IV) with guanylin (0.1-10 mg/kg) show a rapid, transient increase in urinary sodium and potassium excretion (within 30-60 minutes), confirming its natriuretic and diuretic activity. It is also expressed in the kidney, where it may function as a natriuretic hormone.
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| Enzyme Assay |
For the activation of guanylyl cyclase C (GC-C), T84 human colon cancer cells are seeded in 24-well plates (5 × 10⁵ cells/well) and grown to confluence. The culture medium is removed, and the cells are washed with PBS containing 0.5 mM IBMX (phosphodiesterase inhibitor). Guanylin (mouse, rat) TFA (0.01-1000 nM) is added in DMEM with 0.5 mM IBMX and incubated at 37degC for 15 minutes. After stimulation, the medium is aspirated, and cells are lysed with 0.1 M HCl. Cell lysates are centrifuged (1000g, 10 min, 4degC), and the supernatant is collected. cGMP levels are determined by competitive ELISA (or RIA). Guanylin typically stimulates cGMP production with an EC₅0 of ~3.4 ng/ml. For the control, heat-stable enterotoxin (STa, 10-100 nM) is used.
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| Cell Assay |
For Ussing chamber experiments, T84 cell monolayers are grown on Snapwell inserts and mounted in an Ussing chamber. Guanylin (mouse, rat) TFA (0.1-100 nM) is added to the apical side, and short-circuit current (Isc) is measured. An increase in Isc indicates activation of CFTR-mediated Cl- secretion. This effect is inhibited by the CFTR inhibitor CFTRinh-172. For GC-C binding assays, recombinant human GC-C (10-100 nM) is incubated with increasing concentrations (0.01-1000 nM) of biotinylated or fluorescently labeled guanylin in binding buffer (50 mM HEPES, pH 7.4, 100 mM NaCl, 5 mM MgCl2, 0.5% BSA) at 4degC for 2 h. Unbound ligand is removed by filtration. Bound ligand is detected using Europium-labeled streptavidin or by fluorescence polarization. Kd is calculated (typically in the low nanomolar range). For receptor binding, competition studies with the unlabeled peptide are performed. IC₅0 values are used to calculate binding affinity. For enterotoxin STa assays, STa is used as the positive control (EC₅0 ~1-10 nM). The activity of guanylin is approximately 100-fold weaker than STa in stimulating GC-C.
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| Animal Protocol |
For chloride secretion and cGMP assays, T84 cells are used as described above. For Western blotting, cells are lysed after guanylin treatment, and the expression of CFTR or other signaling molecules (e.g., PKG, VASP) is assessed. To assess whether guanylin induces apoptosis in colon cancer cells, cells are treated with 1-1000 nM guanylin for 24-72 h. Apoptosis is assessed by Annexin V/PI staining, caspase-3/7 activity, and Western blot for PARP cleavage.
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| ADME/Pharmacokinetics |
In vivo studies: to measure renal function, male Sprague-Dawley rats (250-300 g, n=6) are anesthetized, and a urinary catheter is inserted. Guanylin (mouse, rat) TFA (0.5-5 mg/kg) is administered via a bolus IV injection. Urine is collected at 0.5, 1, 2, and 4-hour intervals; urine volume and sodium/potassium concentration are measured by flame photometry. Blood samples are collected for plasma cGMP measurement by ELISA. For intestinal studies, mice (C57BL/6, n=8) are given guanylin (0.1-10 mg/kg) by intraperitoneal (IP) injection or oral gavage. Intestinal fluid accumulation is measured by the weight-to-length ratio of the small intestine after 2 hours, and the concentration of cGMP in intestinal tissue homogenates is measured by ELISA. All animal studies must be approved by the IACUC.
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| Toxicity/Toxicokinetics |
As a peptide, guanylin has a short half-life in plasma (t½ <15 minutes). It is rapidly cleared by the kidneys and degraded by proteases. It is not orally bioavailable. The guanylin analog linaclotide (approved for IBS-C) is a more stable, orally available peptide mimetic.
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| References | |
| Additional Infomation |
Guanylin is generally non-toxic at nanomolar concentrations in vitro. At high doses (>10 mg/kg IP), it may cause transient hypotension and electrolyte loss. It is not genotoxic.
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| Molecular Formula |
C60H90N16O22S4.XC2HF3O2
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| Molecular Weight |
1515.71 (free base)
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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: (1). 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 : ~4.95 mg/mL (~adjust pH to 9 with 1 M NaOH)
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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.) |
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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