Research At a Glance
- Research Category
- Growth Factor & Anabolic Signaling Research
- Peptide Length
- 83 amino acids (Long R3 IGF-1 analogue)
- Purity
- ≥ 98% (HPLC)
- Published Studies
- 50,000+ indexed (IGF-1 literature)
- Storage
- Lyophilized: −20 °C long term, 2–8 °C short term. Reconstituted: 2–8 °C, use within 30 days.
Published-study figures are approximate PubMed result counts and indicate the volume of available literature only. Purity reflects third-party analytical testing on the corresponding lot; see the Quality Assurance Center for lot-matched certificates.
Overview
IGF-1 LR3 (Long Arginine³ Insulin-Like Growth Factor 1) is a synthetic 83-amino-acid analog of human IGF-1, modified with an arginine substitution at position 3 (replacing glutamic acid) and a 13-amino-acid N-terminal extension. These modifications reduce binding affinity to IGF binding proteins (IGFBPs) by roughly 100-fold while preserving full binding affinity to the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase. Because approximately 97% of circulating native IGF-1 is normally sequestered in IGFBP complexes, IGF-1 LR3’s resistance to this sequestration substantially increases its bioavailable fraction and extends its functional half-life to an estimated 20-30 hours, compared to minutes for native IGF-1.
Citation
Francis G.L., et al. (foundational structural characterization)
History
IGF-1 LR3 was engineered from native human IGF-1 through targeted structural modification designed specifically to reduce IGFBP binding while preserving receptor agonism — a strategy that emerged from foundational structural studies of IGF-1/IGFBP interactions in the early 1990s. Since its characterization, research has expanded through signaling studies (notably work on the PI3K/Akt/mTOR and Ras/MAPK/ERK pathways activated downstream of IGF-1R) and applications in muscle satellite cell biology, where its extended half-life makes sustained receptor activation practical in cell culture and animal models without the impractical dosing frequency required by native IGF-1.
Citation
Rommel C., et al.; Bodine S.C., et al. (signaling pathway characterization)
Structure
| CAS # | 143045-27-6 |
|---|---|
| Molecular Formula | C400H625N111O115S9 |
| Molecular Weight | 9117.60 g/mol |
| UNII | M9L22Y19H9 |
Research Findings
IGF-1 LR3 has been studied primarily in muscle biology, cell signaling, and metabolic research models.
Key Areas of Research
- Musculoskeletal: Satellite cell activation and proliferation, muscle protein synthesis via PI3K/Akt/mTOR/p70S6K signaling
- Cell signaling: IGF-1R activation, IRS-1/IRS-2/Shc adaptor protein engagement, dual pathway activation (PI3K/Akt and Ras/MAPK/ERK)
- Metabolic: Cross-reactivity with insulin receptor and hybrid IGF-1R/IR receptors, nutrient partitioning research
- Pharmacokinetic: IGFBP-resistance mechanism, extended bioavailability research relative to native IGF-1
Summary
Together, these findings position IGF-1 LR3 as a widely used tool for studying sustained IGF-1 receptor activation in muscle and cell-signaling research, where its resistance to IGFBP sequestration solves a practical limitation of native IGF-1’s very short half-life. No human pharmacokinetic data have been published for IGF-1 LR3 specifically; all pharmacokinetic and efficacy findings derive from animal and cell culture models.
Citation
Francis G.L., et al.
References
- Francis G.L., et al. (1992). Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency. Journal of Molecular Endocrinology.
- Rommel C., et al. Mediation of IGF-1-induced skeletal myotube hypertrophy by PI3K/Akt/mTOR and PI3K/Akt/GSK3 pathways. Nature Cell Biology.
- Bodine S.C., et al. Akt/mTOR pathway is a crucial regulator of skeletal muscle hypertrophy and can prevent muscle atrophy in vivo. Nature Cell Biology.
Source
Literature available via PubMed — IGF-1 LR3 and skeletal muscle research .
Certificate of Analysis
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