IGF-1 LR3 (Insulin-like Growth Factor 1, Long R3) is a recombinant analogue of endogenous IGF-1 featuring two modifications: an arginine substitution at position 3 (R3) and a 13-amino acid N-terminal extension. These modifications dramatically reduce its binding affinity to IGF-binding proteins (IGFBPs), which normally sequester approximately 99% of circulating IGF-1, limiting its bioavailability. The result is a compound with significantly longer effective half-life and greater receptor engagement.
Researchers have studied IGF-1 LR3 as a tool to interrogate IGF-1 receptor (IGF-1R) biology without the confounding influence of IGFBP sequestration. Studies have examined its effects on cell proliferation, differentiation, and survival signaling through PI3K/Akt and MAPK/ERK pathways in various cell types including muscle cells, neurons, and cancer cell lines. Research has explored how reduced IGFBP binding affects tissue distribution and receptor occupancy compared to native IGF-1.
Preclinical studies in animal models have examined IGF-1 LR3’s effects on muscle protein synthesis, nitrogen retention, and hyperplasia versus hypertrophy metrics in skeletal muscle. Research has also explored its influence on satellite cell activation and adipose tissue metabolism. Its enhanced bioavailability compared to native IGF-1 makes it a valuable pharmacological tool for studying IGF-1 receptor signaling pathways across diverse cell types.
For research use only. Not for human consumption. Iron Prairie Labs products are intended for qualified researchers and laboratory use only.
