IGF-1 LR3

Product Details

IGF-1 LR3 (Long R3 IGF-1) — Research Grade Recombinant Protein, ≥95% Purity

Long-acting IGF-1 analog. IGF-1 receptor agonist. Lyophilized powder. Lot-specific COA included.

IGF-1 LR3 is a recombinant analog of human insulin-like growth factor 1 (IGF-1), engineered with two structural modifications that fundamentally alter its pharmacokinetic profile. The first is a substitution of arginine for glutamic acid at position 3 (the “R3” modification). The second is a 13-amino-acid N-terminal extension. Together, these changes produce a protein with markedly reduced affinity for IGF-binding proteins (IGFBPs) compared with native IGF-1.

The consequence of this reduced IGFBP binding is a substantially extended half-life. While native IGF-1 has a circulating half-life of approximately 10–15 minutes due to rapid sequestration by IGFBPs, IGF-1 LR3 has a reported half-life of approximately 20–30 hours. This extended duration is the defining characteristic of the molecule: it remains in circulation and available to bind the IGF-1 receptor (IGF-1R) far longer than the native hormone.

IGF-1 LR3 acts as an agonist at IGF-1R, activating the canonical PI3K-Akt and MAPK/ERK signaling pathways that regulate protein synthesis, cell-cycle progression, and cell survival. Because it engages the same receptor as native IGF-1, its downstream signaling is generally presumed to be comparable, although the altered binding characteristics may influence the magnitude or temporal dynamics of pathway activation.

Supplied as a sterile-filtered, lyophilized powder for in vitro and preclinical research applications. Each lot is independently verified for purity and identity and ships with a Certificate of Analysis.

Specifications

Note: IGF-1 LR3 is a recombinant protein and should not be confused with synthetic peptides. Molecular weight is approximately 9.1 kDa. Some suppliers list a CAS number of 123618-03-1 for a related fragment; the correct CAS for the full 83-residue recombinant analog is 946870-92-4. Verify the exact form, molecular weight, and purity against the Certificate of Analysis supplied with your lot.

Research applications

IGF-1 LR3 is used in laboratory settings to investigate:

• IGF-1 receptor signaling — activation of IGF-1R and downstream PI3K-Akt and MAPK/ERK pathways in cell culture models

• IGFBP interaction research — the reduced IGFBP affinity that distinguishes LR3 from native IGF-1, and its effects on bioavailability and clearance

• Myoblast proliferation and differentiation — IGF-1 signaling in skeletal muscle cell models, with in vitro data showing increased myotube diameter and support for growth-related cellular phenotypes

• Gastrointestinal tissue growth — prolonged administration of IGF peptides enhancing growth of gastrointestinal tissues in normal rats, with LR3 showing enhanced potency compared to native IGF-1

• Cell culture and bioprocessing — IGF-1 LR3 is widely used as a cell culture reagent for large-scale culturing, where its extended half-life and reduced IGFBP sequestration make it more effective than native IGF-1

• Comparative IGF analog pharmacology — head-to-head comparison of LR3 versus native IGF-1 for receptor binding, potency, and metabolic stability

• Analytical method development — LC-MS/MS quantification and reference standard preparation for recombinant IGF analog analysis

Handling and storage

Reconstitute under aseptic conditions using sterile water or an appropriate aqueous buffer. IGF-1 LR3 is soluble in water. Aliquot immediately after reconstitution to avoid repeated freeze-thaw cycles. Lyophilized powder is stable for up to 2 years at −20 °C under sealed, desiccated, light-protected conditions. Reconstituted solutions should be stored at 2–8 °C and used within 14–21 days. Do not freeze reconstituted solution.

For laboratory use by qualified personnel only.