IGF-1 LR3 (Long Arg3 Insulin-like Growth Factor-1) is a recombinant IGF-1 analogue with a 13-amino-acid N-terminal extension and Glu-to-Arg substitution at position 3. CAS: 946870-92-4 | MW: ~9,117 Da | 83 amino acids. Extended half-life of ~20-30 hours (vs ~10-20 minutes for native IGF-1) due to dramatically reduced IGFBP binding affinity. Supplied at ≥99% purity.

Research Background

Native IGF-1 has a short plasma half-life due to rapid binding to IGF-binding proteins (IGFBPs). The LR3 modification (Arg substitution at position 3 plus N-terminal extension) dramatically reduces IGFBP affinity, extending functional half-life approximately 20-30x. This makes IGF-1 LR3 invaluable for studying sustained IGF-1 receptor signalling without IGFBP sequestration confounds, enabling longer-window experimental designs not possible with the native hormone.

Mechanism of Action & Research Applications

IGF-1 LR3 activates the IGF-1 receptor (IGF1R) tyrosine kinase, initiating downstream PI3K/AKT/mTOR and RAS/MAPK signalling cascades fundamental to cellular growth, proliferation, survival, and differentiation. Applications: cell proliferation assays; myocyte differentiation studies; satellite cell activation models; anti-apoptosis pathway investigations; GH axis research; and positive controls in IGF-1 receptor pharmacology studies.

Storage & Handling

• Long-term storage: -80°C recommended; -20°C acceptable up to 6 months
• Short-term storage: 2-8°C for 7-14 days after reconstitution; prepare fresh when possible
• Reconstitution: Dissolve in 0.1% acetic acid or sterile water with 0.1% BSA to prevent adsorption; avoid PBS alone
• Handling: Recombinant proteins are sensitive – aliquot immediately; use low-binding tubes to prevent surface adsorption

Related Research Compounds

Often studied alongside upstream GH axis compounds: HGH 10 IU, CJC-1295 + Ipamorelin 10mg, and Ipamorelin 5mg.

For research use only. Not for human or animal consumption. Not a medicinal product.