Overview
IGF-1 LR3 (Long R3 IGF-1) is an engineered analog of human insulin-like growth factor-1 carrying two modifications: a 13-amino-acid N-terminal extension and an arginine-for-glutamate substitution at position 3. Together these changes markedly lower the molecule's affinity for the IGF-binding proteins (IGFBPs) that normally sequester native IGF-1, extending its functional half-life in the research literature to roughly 20–30 hours. It is a single-chain polypeptide produced recombinantly for laboratory use. As a folded protein it is handled as a labile macromolecule rather than a simple peptide.
Mechanism as studied
The research literature characterizes IGF-1 LR3 as an agonist at the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase. Ligand binding drives receptor autophosphorylation and recruitment of adaptor proteins, activating the PI3K/Akt and Ras/MAPK (ERK) signaling cascades associated with cell survival, proliferation, and protein synthesis. In myogenic culture systems the literature describes satellite-cell proliferation and differentiation endpoints downstream of these pathways. The reduced IGFBP affinity conferred by the analog's modifications is characterized as prolonging receptor availability relative to native IGF-1.
Research context
Contexts in which this compound appears in the in-vitro and preclinical research literature:
- Myoblast and satellite-cell culture: proliferation and differentiation under IGF-1R activation.
- PI3K/Akt and MAPK/ERK pathway-signaling endpoints in cultured cells.
- Comparative binding assays against the IGF-binding proteins relative to native IGF-1.
- Preclinical models characterizing extended half-life and systemic IGF-1R signaling.
- Cell-survival and anti-apoptotic signaling studies across cultured lineages.
Handling & storage
Supplied as a lyophilized protein for laboratory reconstitution. Reconstitute gently with bacteriostatic water (or the diluent specified by your protocol) to the working concentration required (e.g. adding 1 mL to the 1 mg vial yields 1 mg/mL). Add diluent slowly against the vial wall and swirl; do not shake or vortex, as agitation can denature the protein. Aliquot after reconstitution to avoid repeated freeze–thaw.
Store the sealed lyophilized vial at −20 °C protected from light. Reconstituted protein is labile — keep refrigerated at 2–8 °C, use within a short assay window, and avoid repeated freeze–thaw.
Certificates of analysis
A certificate of analysis for the current lot is in preparation and will be published in the certificate library. Lot documentation is available on request for this compound.
Order IGF-1 LR3
Lot-traceable, certificate-backed, and shipped cold-chain from the US.
For research use only
This guide is reference material for qualified researchers. The compound is an analytical-grade reference material supplied strictly for in-vitro laboratory research and development — not a drug, supplement, or medical device, and not for human or animal consumption or any therapeutic, clinical, or diagnostic use. No medical claims are made or implied.
