Description
IGF-1 LR3 is a synthetic 83-amino acid analog of human insulin-like growth factor 1, engineered with two structural modifications that distinguish its research profile from native IGF-1. An arginine substitution at position 3 and a 13-amino acid N-terminal extension reduce binding affinity to IGF-1 binding proteins (IGFBPs) by approximately 1000-fold while preserving IGF-1 receptor (IGF-1R) binding capacity. As the primary downstream signal of GH axis activation, the IGF-1R biology that IGF-1 LR3 probes connects directly to the growth hormone peptide research landscape, while the compound’s structural independence from IGFBP regulation makes it a distinct experimental tool from MGF, the locally expressed IGF-1 splice variant studied for satellite cell activation independently of systemic IGF-1 signaling.
Chemical Information
- Chemical Name: IGF-1 LR3 (Long Arg3 IGF-1; des(1-3)IGF-1 with N-terminal extension)
- Also Known As: Long R3 IGF-1; LR3-IGF-1; Receptor Grade IGF-1
- Compound Class: Synthetic recombinant IGF-1 analog (IGFBP-resistant)
- Length: 83 amino acids (native IGF-1 is 70 amino acids; LR3 adds 13-amino acid N-terminal extension)
- Key Modifications: Arg3 substitution; 13-amino acid N-terminal extension
- Molecular Weight: approximately 9,117 Da
- Primary Receptor: IGF-1R (receptor tyrosine kinase; Kd preserved relative to native IGF-1)
- IGFBP Binding: Reduced approximately 1000-fold relative to native IGF-1
- Production: Recombinant expression
Applications
- IGF-1 receptor signaling research in cell-based models requiring sustained receptor activation. The extended half-life and reduced IGFBP interference make IGF-1 LR3 the preferred tool over native IGF-1 in multi-day culture protocols where receptor occupancy consistency matters
- PI3K/Akt/mTOR pathway studies. IGF-1R activation drives PI3K recruitment, Akt phosphorylation, and mTOR complex activation. IGF-1 LR3 provides sustained IGF-1R engagement for experiments examining how this cascade regulates protein synthesis initiation and GLUT4 translocation over extended observation windows
- MAPK/ERK pathway research: the second major downstream cascade activated by IGF-1R. IGF-1 LR3 is used in models examining cell proliferation and differentiation signaling where MAPK/ERK output is the primary readout
- Satellite cell activation and differentiation research. IGF-1R engagement drives satellite cell transition from quiescence through proliferation to differentiation. IGF-1 LR3 provides a defined receptor activation tool for studying these transitions in skeletal muscle progenitor cell models
- IGFBP interaction studies. The 1000-fold reduction in IGFBP binding makes IGF-1 LR3 useful as a comparative reference compound in studies examining how IGFBP sequestration affects IGF-1R signaling availability in serum-containing systems
- IGF-1R and insulin receptor hybrid receptor research. IGF-1R and the insulin receptor share structural homology and form hybrid receptors in some cell populations; IGF-1 LR3’s sustained receptor engagement enables examination of hybrid receptor biology and the potential for metabolic cross-reactivity in research models
- Neuronal and CNS signaling. IGF-1R is expressed in multiple CNS cell populations; IGF-1 LR3 is studied in neuronal and glial cell models where the extended half-life enables observation of longer-duration receptor-mediated neuroprotective signaling
Storage and Handling
Store lyophilized powder at -20C for long-term stability, or at 2-8C for short-term use. Protect from heat, moisture, and direct light. Reconstitute in sterile acidic buffer (0.1% acetic acid) or as specified in the certificate of analysis; avoid alkaline conditions which can degrade the peptide. Reconstituted solutions show greater than 90% bioactivity retention after 48 hours at 37C in serum-containing media. Avoid repeated freeze-thaw cycles to maintain compound integrity.
Compliance Notice
IGF-1 LR3 isfor laboratory research use only. It is not for human or veterinary use and carries no therapeutic, diagnostic, or clinical indication. This product has not been evaluated by the FDA. By purchasing this product, the buyer confirms that they will follow appropriate institutional safety procedures and use it exclusively for controlled research.
