| Size | Price | Stock | Qty |
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| 1mg |
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| 100mg | |||
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| Targets |
The primary targets of Leptin (22-56), human are the leptin receptors (Ob-Rs), which exist in several isoforms. The long form of the leptin receptor (Ob-Rb) is the main signaling-competent isoform, which activates the JAK-STAT signaling pathway upon leptin binding. The peptide fragment mediates its effects through a variety of Ob-R subtypes. In the adrenal cortex, Leptin (22-56) directly inhibits corticosterone production, suggesting that this fragment acts on adrenal leptin receptors to modulate steroidogenesis. The fragment's ability to inhibit corticosterone production without affecting cell proliferation indicates that it specifically targets steroidogenic pathways rather than general cellular growth. Leptin (22-56) may also interact with other leptin receptor isoforms to modulate energy homeostasis and neuroendocrine function.
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| ln Vitro |
Human leptin (22–56) is a leptin fragment that suppresses the generation of corticosterone while having no effect on the growth of adrenocortical cells in culture. The development of cultured rat adrenocortical cells and leptin release may be directly inhibited by leptin (22–56) [1]. Leptin (22–56) suppresses appetite and may promote erythropoiesis [2].
In vitro studies demonstrate that Leptin (22-56), human directly inhibits corticosterone production in cultured rat adrenocortical cells. The peptide fragment shows no effect on the proliferation of cultured adrenocortical cells, indicating that its effects are specific to steroidogenesis rather than cell growth. This suggests that Leptin (22-56) may directly inhibit adrenal cortical cell secretion of corticosterone, potentially by modulating the activity of enzymes involved in steroid biosynthesis. The fragment's activity in the adrenal cortex highlights its role in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Leptin (22-56) acts through a variety of Ob-R subtypes to mediate these effects. The fragment may also have effects on other cell types and tissues where leptin receptors are expressed, although these have not been extensively studied. |
| ln Vivo |
In vivo studies of Leptin (22-56), human have been limited, with most research focusing on its in vitro effects. However, the fragment's ability to inhibit corticosterone production suggests potential in vivo effects on the HPA axis and stress responses. Leptin and its fragments are involved in the regulation of appetite, energy expenditure, and neuroendocrine function in vivo. The peptide fragment may also inhibit food intake, consistent with the known role of full-length leptin in appetite suppression. In animal models, leptin fragments have been studied for their effects on metabolism, body weight, and endocrine function. However, detailed in vivo protocols and efficacy data specifically for Leptin (22-56) are limited. The fragment's short half-life and rapid degradation are typical of peptide-based research reagents.
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| Enzyme Assay |
For receptor binding assays, competition binding studies are performed using membrane preparations from cells expressing recombinant Ob-R receptors. Membranes are incubated with radiolabeled leptin ([¹²⁵I]-leptin, typically 0.1-1 nM) and varying concentrations of unlabeled Leptin (22-56) (0.001-100 µM) in binding buffer (50 mM HEPES, pH 7.4, 5 mM MgCl₂, 0.1% BSA, and protease inhibitors) at 4°C for 16-24 hours. Bound and free radioligand are separated by centrifugation or filtration, and radioactivity is counted. Specific binding is defined as total binding minus non-specific binding (determined in the presence of 1 µM unlabeled full-length leptin). Ki values are calculated from IC50 values using the Cheng-Prusoff equation. For functional assays, cells expressing Ob-Rb receptors are treated with Leptin (22-56) and downstream signaling (JAK2 phosphorylation, STAT3 phosphorylation, and transcriptional activation of STAT3-responsive reporter genes) is measured by Western blot or luciferase reporter assays.
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| Cell Assay |
For in vitro studies on adrenocortical cells, primary rat adrenocortical cells are isolated from adrenal glands and cultured in appropriate medium (e.g., DMEM/F12 with 10% FBS and antibiotics). Cells are seeded in 24-well or 6-well plates at a density of 1-5 × 10⁵ cells/well and allowed to attach for 24-48 hours. Leptin (22-56), human is dissolved in sterile water or PBS and diluted in culture medium to final concentrations (typically 0.01-10 µM). Cells are treated with the peptide for 24-72 hours. Corticosterone production is measured by radioimmunoassay (RIA) or ELISA of the culture supernatant. Cell proliferation is assessed by [³H]-thymidine incorporation or BrdU incorporation assays. For mechanistic studies, cells are lysed and analyzed for steroidogenic enzyme expression (e.g., CYP11A1, CYP21A1, CYP11B1) by Western blot or qRT-PCR. For cell viability assays, cells are treated with the peptide and viability is assessed by MTT or trypan blue exclusion.
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| Animal Protocol |
No standard in vivo protocols exist specifically for Leptin (22-56), human, as the fragment is primarily used as a research reagent for in vitro studies. If used in animal studies, typical protocols for peptide administration would involve subcutaneous, intraperitoneal, or intravenous injection in mice or rats at doses of 0.1-10 mg/kg. The peptide would be administered daily or on a scheduled basis for 1-4 weeks. Endpoints would include food intake, body weight, plasma corticosterone levels, and metabolic parameters. However, such studies are not typical for this specific fragment, and no detailed protocols are reported in the literature.
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| ADME/Pharmacokinetics |
Pharmacokinetic data for Leptin (22-56), human are limited, as the peptide is used as a research reagent rather than a therapeutic agent. As a 35-amino acid peptide, the fragment is susceptible to rapid proteolytic degradation by serum and tissue peptidases, resulting in a short plasma half-life (likely minutes to hours). The peptide is not expected to have significant oral bioavailability and is typically administered by injection. Its metabolism involves cleavage by endopeptidases and exopeptidases, producing smaller peptide fragments and free amino acids. Tissue distribution is limited due to its hydrophilic nature and high molecular weight (3950.52). These pharmacokinetic limitations are typical of peptide-based research reagents and must be considered when designing any in vivo experiments.
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| Toxicity/Toxicokinetics |
Toxicological data for Leptin (22-56), human are limited, as the peptide is intended for research use only and has not been developed as a therapeutic agent. In cellular assays, the fragment shows activity at micromolar concentrations and is generally well-tolerated. The fragment shows no effect on the proliferation of cultured adrenocortical cells, suggesting that it does not have cytotoxic effects at the concentrations used. No acute toxicity, organ-specific toxicity, or mutagenicity data have been reported. As with all research chemicals, appropriate safety precautions should be taken when handling Leptin (22-56), human, including the use of personal protective equipment and work in a well-ventilated area.
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| References |
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| Additional Infomation |
Leptin (22-56), human is a peptide fragment corresponding to amino acids 22-56 of the human leptin protein, a hormone produced primarily by adipocytes that regulates energy homeostasis, appetite, and metabolism. The fragment acts through various subtypes of Ob-R (leptin) receptors. In vitro, it inhibits corticosterone production in cultured rat adrenocortical cells without affecting cell proliferation. The fragment may also inhibit food intake, consistent with leptin's role in appetite suppression. Its molecular formula is C₁₇₁H₂₉₈N₅₀O₅₆ with a molecular weight of 3950.52. Leptin (22-56), human is used as a research tool for studying leptin signaling, leptin receptor pharmacology, and the regulation of adrenal steroidogenesis. It is strictly for research use only and has not entered clinical trials.
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| Molecular Formula |
C171H298N50O56
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| Molecular Weight |
3950.54
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| CAS # |
183598-56-3
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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) |
DMSO : ≥ 100 mg/mL (~25.31 mM)
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| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (0.63 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. Solubility in Formulation 2: ≥ 2.5 mg/mL (0.63 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 corn oil and mix evenly. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 0.2531 mL | 1.2656 mL | 2.5313 mL | |
| 5 mM | 0.0506 mL | 0.2531 mL | 0.5063 mL | |
| 10 mM | 0.0253 mL | 0.1266 mL | 0.2531 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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