IGF-1LR3

IGF-1 LR3 (Long R3 IGF-1) is a recombinant analogue of insulin-like growth factor 1 engineered for extended half-life. The modifications consist of two changes from native IGF-1: a 13-amino acid N-terminal extension and an arginine substitution at position 3. Together these modifications reduce binding to IGF binding proteins (IGFBPs), which in the native system sequester IGF-1 and limit its bioavailability. The result is approximately 10-15 times longer half-life than native IGF-1 and substantially higher bioavailability due to reduced IGFBP binding.

IGF-1 is the primary mediator of growth hormone's anabolic effects. After GH stimulates hepatic IGF-1 production, circulating IGF-1 binds IGF-1 receptors in muscle, bone, and other tissues to drive protein synthesis, cell proliferation, and differentiation. IGF-1 receptor signaling activates PI3K/Akt and MAPK pathways -- core regulators of cell growth and survival. In skeletal muscle specifically, IGF-1 signaling promotes muscle protein synthesis, satellite cell activation, and hypertrophy. IGF-1 LR3's extended activity makes it useful for studying IGF-1 receptor biology over longer time windows than native IGF-1 allows.

One caveat worth noting for research design: the reduced IGFBP binding means IGF-1 LR3 behaves differently from endogenous IGF-1 in systems where binding proteins play a physiological role. Studies examining IGFBP-IGF interactions or physiological IGF-1 signaling should account for this difference.

Specifications

Storage

Store at -20°C before reconstitution. Reconstitute with 0.1% acetic acid initially, then dilute with PBS or cell culture medium. Refrigerate reconstituted solutions at 2-8°C and use within 7-14 days. Avoid repeated freeze-thaw cycles.

IGF-1 LR3 is supplied for laboratory research use only. Not approved for human use. Handle in compliance with institutional biosafety guidelines.