IGF-1 LR3

Mechanism

IGF-1 LR3 (Long Arg3 IGF-1) is an 83-amino acid analog of human IGF-1 engineered with two key modifications: substitution of glutamic acid with arginine at position 3 (Arg3), and extension of the N-terminus by 13 amino acids. These changes dramatically reduce binding affinity for IGF binding proteins (IGFBPs 1-6), which normally sequester and inactivate circulating IGF-1. As a result, IGF-1 LR3 has a significantly longer half-life and greater bioavailability than native IGF-1. It activates the IGF-1 receptor (IGF-1R) to stimulate protein synthesis, glucose uptake, and cell proliferation through the PI3K/Akt and MAPK/ERK signaling pathways.

What the literature has looked at

• Studies have investigated enhanced anabolic signaling due to reduced IGFBP sequestration
• Research has examined muscle hypertrophy and recovery signaling in cell culture and animal models
• Studies have explored its effects on glucose metabolism and insulin sensitivity pathways
• Biotechnology applications in cell culture media and bioprocess optimization

Research context, not a claim about what this compound does. Research Use Only — not for human or animal consumption. 21+.

Cited work

• Francis GL, et al. Insulin-like growth factors 1 and 2 in bovine colostrum. Sequences and biological activities compared with those of a potent truncated form. Biochem J. 1988;251(1):95-103.

  Characterized the enhanced biological potency of IGF-1 analogs with reduced IGFBP binding, establishing the pharmacological rationale for the LR3 modification.

• Tomas FM, et al. Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection. J Endocrinol. 1996;150(1):77-84.

  Demonstrated that IGF-1 LR3 maintained its superior potency over native IGF-1 in modulating nitrogen retention and anabolic signaling pathways when administered by injection in research models.

Properties

type

Peptide (IGF-1 analog, 83 amino acids)