IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) (1mg)

IGF-1 LR3 Peptide (Lyophilized)

Sequence: Modified Human IGF-1 (83 Amino Acids) Format: Sterile Lyophilized Powder (Vial) Modifications: Glu3→Arg3 Substitution + 13 AA N-Terminal Extension Purity: >95% (SDS-PAGE / Receptor Grade) Content: 1mg per vial

Product Overview

IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a recombinant analog of human IGF-1, engineered to overcome the pharmacokinetic limitations of the native hormone.

While native IGF-1 has a half-life of minutes and is tightly sequestered by binding proteins (IGFBPs), IGF-1 LR3 incorporates two critical modifications:

1. Arg3 Substitution: Prevents binding to IGFBPs, keeping the peptide "free" and bioactive.

2. N-Terminal Extension: Increases metabolic stability and half-life to 20-30 hours.

This design creates a molecule that is 2-3 times more potent than native IGF-1 in driving anabolism and nitrogen retention in research models.

Mechanism of Action: The Unbound Agonist

IGF-1 LR3 bypasses the body's natural regulatory buffers to deliver sustained signaling.

• PI3K/Akt/mTOR Pathway: Activates the primary engine of protein synthesis. It recruits IRS-1 and PI3K, leading to the phosphorylation of mTOR, which drives ribosomal activity and muscle hypertrophy.

• FoxO Suppression: Phosphorylates FoxO transcription factors, trapping them in the cytoplasm. This prevents them from transcribing muscle atrophy genes (Atrogin-1, MuRF1), effectively blocking protein breakdown.

• Glucose Partitioning: Cross-activates Insulin/IGF-1 Hybrid Receptors on muscle cells, driving GLUT4 translocation and glucose uptake independently of insulin levels.

Key Research Applications

1. Musculoskeletal Hypertrophy IGF-1 LR3 is the gold standard for research into rapid muscle growth.

• Potency: In nitrogen balance studies (Tomas et al.), LR3 was significantly more effective than native IGF-1 at promoting weight gain and nitrogen retention, even with once-daily dosing.

• Differentiation: Promotes both the proliferation of satellite cells (via MAPK) and their fusion into myotubes (via Myogenin), supporting hyperplasia and hypertrophy.

2. Metabolic Partitioning Investigated for its "leaning" effect.

• Nutrient Shuttling: Drives glucose and amino acids into muscle tissue while suppressing insulin secretion. Low insulin disinhibits lipolysis (fat breakdown), shifting the metabolic preference toward burning fat for fuel.

3. Cell Culture & Bioengineering Widely used in serum-free media to maintain stem cells (iPSCs/hESCs). Its stability allows for less frequent media changes while maintaining pluripotency and survival better than native growth factors.

Storage & Handling

• Physical State: Lyophilized (Freeze-Dried) Powder.

• Storage (Powder): Store at -20°C (Freezer). Stable for up to 12 months.

• Reconstitution:

  • Solvent: 10-100mM HCl or Acetic Acid is often recommended for the initial dissolution to prevent aggregation, followed by dilution with sterile buffer. Alternatively, use Bacteriostatic Water if using immediately.

• Storage (Liquid): Store at 4°C. Very sensitive to degradation. Use within 7 days. Avoid freeze-thaw cycles.

Disclaimer

FOR RESEARCH USE ONLY. This product is a chemical compound intended strictly for laboratory research and development. It is not approved by the FDA for clinical use, diagnostics, or therapeutic procedures in humans or animals. The physiological and toxicological properties of this chemical have not been fully investigated.