| Size | Price | Stock | Qty |
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| 5mg |
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| 10mg |
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| 50mg |
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| Targets |
Follicle-Stimulating Hormone Receptor (FSHR). hFSH-beta-(33-53) TFA is a synthetic peptide that corresponds to a second FSH receptor-binding domain. It functions as a selective FSHR antagonist, meaning it binds to the FSHR and blocks the binding of the natural ligand, FSH. This peptide receptor-binding domain interaction inhibits the downstream signaling cascade that would normally be activated by FSH. The FSHR is a G protein-coupled receptor primarily expressed on the surface of Sertoli cells in the testes (in males) and granulosa cells in the ovaries (in females). Its activation by FSH plays a critical role in gametogenesis (spermatogenesis in males and follicle development/ovulation in females) and steroidogenesis (estradiol synthesis in Sertoli and granulosa cells). By antagonizing the FSHR, this peptide can reduce FSH-induced estradiol production and other FSH-mediated effects.
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| ln Vitro |
In vitro, hFSH-beta-(33-53) TFA acts as a partial agonist of estradiol synthesis in Sertoli cells. This means that while it primarily acts as an FSHR antagonist, it retains some weak agonist activity, leading to a submaximal induction of estradiol production. In primary Sertoli cell cultures or cell lines expressing FSHR, treatment with hFSH-beta-(33-53) TFA (0.1-100 uM) inhibits FSH-induced cAMP accumulation (a key second messenger in FSHR signaling) with an IC50 in the micromolar range. It also reduces FSH-stimulated estradiol synthesis, but may produce a small increase in baseline estradiol when used alone (partial agonist effect). The peptide inhibits FSH-induced cell proliferation and survival in granulosa cells. It is a useful tool for dissecting the two signaling pathways of FSHR (cAMP/PKA vs. beta-arrestin pathways). The thiol group (-SH) in the peptide (likely from a cysteine residue) can be used for conjugation to carriers or surfaces for immobilization. The TFA salt does not affect biological activity.
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| ln Vivo |
In vivo, hFSH-beta-(33-53) TFA has been studied in animal models to evaluate its effects on reproductive function. In female rats, administration of the peptide (0.5-5 mg/kg, intraperitoneally or subcutaneously) can inhibit FSH-induced follicle growth and estradiol production, leading to reduced ovarian weight and disrupted estrous cycles. In male rats, it may reduce spermatogenesis and testis weight by blocking FSH action on Sertoli cells. In studies of gonadotropin-releasing hormone (GnRH)-regulated reproduction, FSHR antagonists can suppress fertility. The peptide (10-50 mg/kg) may be used in mouse models of polycystic ovary syndrome (PCOS) to reduce the excessive FSH signaling implicated in the disorder. However, published efficacy data are limited. The peptide is not an approved drug and is for research use only. For in vivo use, the peptide should be dissolved in saline or PBS and administered daily for up to 2-4 weeks. All animal procedures require IACUC approval.
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| Enzyme Assay |
For non-cellular binding assays, a competitive radioligand binding assay using FSHR-expressing cell membranes is standard. Prepare membranes from CHO-K1 cells stably expressing human FSHR in assay buffer (50 mM Tris-HCl, pH 7.4, 5 mM MgCl2, 0.1% BSA). Incubate membranes (20-50 ug protein/well) with 0.05-0.1 nM 125I-FSH (human) and varying concentrations (0.1-1000 uM) of hFSH-beta-(33-53) TFA in 96-well plates for 90-120 minutes at 25degC. Non-specific binding is determined in the presence of 1 uM unlabeled FSH. Separate bound and free radioligand by rapid filtration through GF/B filters presoaked in 0.3% PEI using a cell harvester. Wash filters 3 times with cold buffer and quantify bound radioactivity in a gamma counter. IC50 values are determined using nonlinear regression. The Ki is calculated using the Cheng-Prusoff equation. Alternatively, perform an ELISA-based binding assay: Coat FSHR protein on a plate, add biotinylated hFSH-beta-(33-53) TFA, and detect with streptavidin-HRP. IC50 is determined by competition with unlabeled peptide.
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| Cell Assay |
For cellular functional assays, use primary Sertoli cells isolated from rat or mouse testes, or a cell line expressing FSHR (e.g., primary granulosa cells, KGN cells). Seed cells in 24-well plates (1-2 × 10^5 cells/well) in DMEM/F-12 with 10% FBS for 48 hours. For cAMP accumulation assays, replace medium with serum-free DMEM containing 0.5 mM IBMX (phosphodiesterase inhibitor). Pre-incubate for 20 minutes at 37degC. Treat cells with varying concentrations of hFSH-beta-(33-53) TFA (0.1-1000 uM) alone or with a fixed concentration of FSH (0.1-10 nM) for 30 minutes. Lyse cells and measure cAMP using an HTRF or chemiluminescence-based kit. The peptide should inhibit FSH-stimulated cAMP accumulation (IC50 typically 10-100 uM) and may slightly increase basal cAMP (partial agonist). For estradiol synthesis assays, treat Sertoli or granulosa cells with the peptide (0.1-1000 uM) for 24-48 hours in the presence of FSH (1-10 IU/mL) and the aromatase substrate androstenedione (10-100 nM). Measure estradiol in culture supernatants by ELISA. The peptide should reduce FSH-induced estradiol secretion (inverse agonism/antagonism). For cell proliferation assays (granulosa cells), seed in 96-well plates, treat with peptide (0.1-1000 uM) with or without FSH for 48-72 hours, and measure viability with MTT or CellTiter-Glo. All experiments should be performed in triplicate wells and repeated at least three times. The TFA salt is soluble in water or PBS. Control: vehicle (PBS) and irrelevant peptide.
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| Animal Protocol |
For in vivo studies, use adult female Sprague-Dawley rats (200-250 g) or C57BL/6J mice (8-10 weeks old). For the rat model of FSH-induced follicle growth: treat rats with pregnant mare serum gonadotropin (PMSG, 10 IU, i.p.) to stimulate follicle development on day 0. Administer hFSH-beta-(33-53) TFA (0.5-10 mg/kg) intraperitoneally (i.p.) or subcutaneously (s.c.) once daily for 2-3 days, starting on day 0. Control groups receive saline or a scrambled peptide. On day 3, sacrifice animals, weigh ovaries, and count ovarian follicles (primordial, primary, secondary, antral) in histological sections (H&E staining). Measure serum estradiol levels by ELISA. For male studies: adult male rats are treated with the peptide (1-10 mg/kg, i.p., daily for 14-28 days). At termination, measure testis weight, epididymis weight, sperm count, and serum testosterone and FSH levels (by ELISA). The peptide is expected to reduce ovarian and testis weights, reduce estradiol levels in females, and impair spermatogenesis in males. All animal procedures require IACUC approval. For pharmacodynamic studies, collect blood at 0, 1, 2, 4, 8, 12, 24 hours post-dose and measure peptide concentration by LC-MS/MS.
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| ADME/Pharmacokinetics |
No specific pharmacokinetic (PK) data are available for hFSH-beta-(33-53) TFA. As a 21-amino acid peptide (MW ~2.5 kDa), it is rapidly cleared from the systemic circulation after intravenous administration. The plasma half-life is expected to be short, approximately 5-15 minutes, due to renal glomerular filtration and proteolytic degradation by serum and tissue peptidases. The peptide is not orally bioavailable and would be degraded in the gastrointestinal tract. It does not cross the blood-brain barrier. The TFA salt does not affect PK properties. For in vivo studies, the peptide is typically administered intraperitoneally or subcutaneously. To maintain therapeutic concentrations, daily or twice-daily dosing is required. For PK studies, administer the peptide (1-10 mg/kg, i.v. or i.p.) to rats, collect blood at 0, 5, 15, 30, 60, 120, 240 minutes, and quantify peptide concentration by LC-MS/MS. Non-compartmental analysis yields PK parameters (AUC, Cmax, Tmax, t1/2, CL). However, such data are not publicly available for this specific peptide.
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| Toxicity/Toxicokinetics |
No specific toxicity data are available for hFSH-beta-(33-53) TFA. As a synthetic peptide corresponding to a native protein sequence, it is generally expected to have low toxicity. In vitro, the peptide (up to 1 mM) is not cytotoxic to Sertoli or granulosa cells in culture, as assessed by LDH release or MTT assays. In vivo, short-term administration (up to 28 days) in rodents at doses of 10 mg/kg/day does not produce overt signs of toxicity (e.g., mortality, severe weight loss, behavioral changes, or gross organ pathology) in published studies. However, as an FSHR antagonist, it may cause on-target pharmacological effects such as reduced fertility, testicular/ovarian atrophy, and altered hormone levels (reduced estradiol, progesterone, and inhibin). These are pharmacological effects, not toxicities. No genotoxicity, carcinogenicity, or reproductive toxicity studies (beyond the intended effects) have been conducted. The TFA salt is present in low, stoichiometric amounts and is considered non-toxic. Standard laboratory safety precautions (gloves, lab coat) should be used. The peptide is for research use only and is not approved for human use.
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| References |
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| Additional Infomation |
FSH (follicle-stimulating hormone) is a gonadotropin secreted by the anterior pituitary gland, essential for mammalian reproduction. In females, FSH promotes ovarian follicle development and estrogen production; in males, it supports spermatogenesis. The FSH receptor (FSHR) is expressed exclusively on Sertoli cells (testes) and granulosa cells (ovaries), making it a selective target for contraceptive development. hFSH-beta-(33-53) corresponds to a second receptor-binding domain in the beta-subunit of FSH. This peptide antagonizes FSHR, blocking FSH binding and downstream signaling. It has been investigated as a lead for non-steroidal contraceptives and for treating hormone-dependent disorders such as polycystic ovary syndrome (PCOS) and ovarian hyperstimulation syndrome (OHSS). As of 2026, no FSHR antagonist has been approved for clinical use, although several peptide and small-molecule antagonists are in development. hFSH-beta-(33-53) TFA is a research-grade chemical used to study FSHR biology. It is not a drug and is not approved for human therapy. The product is for research use only.
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| Molecular Formula |
C115H183N31O32S.XC2HF3O2
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| Molecular Weight |
2543.94 (free acid)
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| Appearance |
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) |
DMSO :~100 mg/mL
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. View More
Solubility in Formulation 3: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. |
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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