IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a synthetic analogue of human IGF-1 featuring two structural modifications: an arginine substitution at position 3 and a 13 amino acid N-terminal extension sequence. These modifications significantly reduce the peptide's affinity for IGF-binding proteins (IGFBPs), which normally sequester approximately 99% of circulating IGF-1, thereby extending its effective half-life in experimental models.
IGF-1 Receptor Signaling Research
Preclinical research has examined IGF-1 LR3's interactions with the IGF-1 receptor (IGF1R), a receptor tyrosine kinase that activates downstream PI3K/Akt and MAPK/ERK signaling cascades upon ligand binding. Studies have investigated its effects on cell proliferation and survival signaling in various cell culture models.
Protein Synthesis and Cellular Growth Research
Research has examined IGF-1 LR3's influence on mTOR pathway activation and downstream protein synthesis regulation in skeletal muscle cell models. Studies have investigated its effects on ribosomal protein S6 kinase activation as markers of translational capacity.
IGFBP Binding Studies
A key area of IGF-1 LR3 research involves comparative studies examining its differential binding to IGF-binding proteins relative to native IGF-1, establishing the pharmacokinetic basis for its extended activity in preclinical models.
• Tomas FM et al. (1993). Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats. Biochemical Journal, 291(3), 729–735.
