IGF1 Human
Description
Introduction to IGF1 Human
Insulin-like Growth Factor 1 (IGF1 Human) is a 70-amino-acid polypeptide hormone with structural similarity to insulin. It plays a critical role in growth regulation, metabolic function, and cellular repair. Produced primarily by the liver under stimulation by growth hormone (GH), IGF1 circulates bound to insulin-like growth factor-binding proteins (IGFBPs), which modulate its bioavailability . IGF1 is essential for postnatal development, skeletal muscle hypertrophy, and tissue regeneration, while dysregulation is linked to cancer, neurodegenerative diseases, and metabolic disorders .
IGF1 Receptor Activation
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Mechanism: IGF1 binding induces autophosphorylation of tyrosine residues on IGF1R, triggering downstream signaling cascades (e.g., PI3K/Akt and MAPK pathways) .
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Dimerization: Cryo-EM studies reveal an asymmetric Γ-shaped IGF1R dimer bound to a single IGF1 molecule, hindering cooperative binding of a second ligand .
Table 1: Comparative Features of IGF1 and Insulin Receptors
| Feature | IGF1 Receptor (IGF1R) | Insulin Receptor |
|---|---|---|
| Homology | 60% with insulin receptor | - |
| Ligand Affinity | Binds IGF1, IGF2, insulin | Primarily binds insulin |
| Signaling Pathways | PI3K/Akt, MAPK | PI3K/Akt, MAPK |
| Functional Role | Growth, survival | Glucose homeostasis |
Key Functions
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Growth and Development: Mediates GH-dependent postnatal growth; knockout mice exhibit severe growth retardation .
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Muscle Maintenance: Promotes skeletal muscle satellite cell proliferation and differentiation, preventing atrophy .
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Metabolic Regulation: Enhances GLUT4 expression and insulin-stimulated glucose uptake in human myotubes .
Disease Associations
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Cancer: Elevated IGF1 levels correlate with increased risk of prostate, breast, and colorectal cancers .
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Neurodegeneration: Dual role in Alzheimer’s and Parkinson’s diseases:
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Cardiovascular Disease: Low IGF1 levels linked to atherosclerosis and heart failure .
Recombinant IGF1 (rhIGF1)
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Therapeutic Use: Mecasermin (synthetic IGF1) treats growth failure in children with severe IGF1 deficiency .
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Clinical Trials:
Table 2: Clinical Outcomes of IGF1 Supplementation
| Condition | Study Outcome | Reference |
|---|---|---|
| ALS | No significant survival benefit | |
| Preterm Brain Injury | Reduced neurodevelopmental deficits | |
| Muscle Atrophy | Enhanced myotube differentiation |
Dietary and Lifestyle Modulation of IGF1
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Protein Intake: Dairy protein (milk, yogurt) increases circulating IGF1 levels, while cheese shows no effect .
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Fiber and Wholegrains: Positive correlation with IGF1, potentially via gut microbiome-derived short-chain fatty acids .
Research Models and Methodologies
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In Vitro Myotube Models: IGF1 supplementation enhances human myotube contractility, oxidative metabolism, and insulin sensitivity .
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Animal Studies: IGF1R inhibition in mice mimics preterm brain injury, highlighting IGF1’s role in neurodevelopment .
Future Directions
Product Specs
The somatomedins, also known as insulin-like growth factors (IGFs), are a family of peptides that play a crucial role in the growth and development of mammals. IGF1 is a key mediator of growth hormone's (GH) growth-promoting effects. Initial research revealed that GH did not directly stimulate sulfate incorporation into cartilage. Instead, it acted through a serum factor initially called 'sulfation factor' and later renamed 'somatomedin.' Three primary somatomedins have been identified: somatomedin C (IGF1), somatomedin A (IGF2), and somatomedin B.
Recombinant Human IGF1 produced in E. coli is a single, non-glycosylated polypeptide chain consisting of 70 amino acids. It has a molecular weight of 7.6 kDa. The purification of IGF-1 is achieved using proprietary chromatographic methods.
The protein was freeze-dried from a concentrated solution in phosphate-buffered saline (PBS) at a pH of 7.0.
Lyophilized IGF1 remains stable at room temperature for up to 3 weeks. However, for long-term storage, it is recommended to store it in a desiccated state at a temperature below -18°C. After reconstitution, IGF1 should be stored at 4°C for 2 to 7 days. For extended storage, it is advisable to add a carrier protein such as HSA or BSA at a concentration of 0.1%. Avoid repeated freeze-thaw cycles.
The purity of IGF-1 is greater than 97.0%, as determined by the following methods:
(a) Reverse-phase high-performance liquid chromatography (RP-HPLC) analysis.
(b) Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis.
The biological activity, assessed using a cell proliferation assay with serum-free human MCF-7 cells, is less than 2 ng/ml. This corresponds to a specific activity greater than 5.0 x 105 IU/mg.
Somatomedin C, IGF-I, IGFI, IGF1, IGF-IA MGF.
Product Science Overview
IGF-1 is a single-chain polypeptide consisting of 70 amino acids with a molecular weight of approximately 7.6 kDa . It shares a high degree of homology with proinsulin, which is reflected in its ability to bind to insulin receptors, albeit with lower affinity . The primary function of IGF-1 is to mediate the effects of growth hormone, promoting growth and development in tissues such as muscle, bone, and cartilage .
Recombinant human IGF-1 is produced using recombinant DNA technology, typically in Escherichia coli (E. coli) expression systems . This method involves inserting the human IGF-1 gene into the bacterial DNA, allowing the bacteria to produce the protein. The recombinant protein is then purified and used for various research and therapeutic applications.
- Research: Recombinant IGF-1 is widely used in scientific research to study its effects on cell growth, differentiation, and survival. It is particularly useful in cancer research, where it is used to investigate the role of IGF-1 in tumor growth and progression .
- Therapeutics: IGF-1 has potential therapeutic applications in treating growth disorders, such as growth hormone insensitivity syndrome (GHIS) and Laron syndrome. It is also being explored for its potential in treating neurodegenerative diseases like Alzheimer’s disease, as low levels of IGF-1 have been linked to the condition .
Recombinant human IGF-1 is typically lyophilized and stored at -20°C to -80°C to maintain its stability . It is essential to avoid repeated freeze-thaw cycles to prevent degradation of the protein. Once reconstituted, the protein should be stored under sterile conditions at 2°C to 8°C for short-term use or at -20°C to -80°C for long-term storage .
