IGF-1 LR3: Scientific Profile
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Long-acting recombinant IGF-1 analog (Long [Arg3]-IGF-I): arginine at position 3 and a 13-aa N-terminal extension (83 aa). IGF-1R agonist with low affinity for IGFBP and a half-life of 20-30 h. CAS 946870-92-4. For research.
IGF-1 LR3 (Long R3 IGF-1, Long [Arg3]-IGF-I) is a recombinant analog of insulin-like growth factor 1 (IGF-1), classified as a long-acting superagonist variant. It derives from human IGF-1 with two modifications: at position 3, arginine (Arg) replaces the native glutamate (Glu3->Arg, hence the designation 'R3'/Arg3), and a 13-amino-acid peptide extension is added at the N-terminus, for a total of 83 amino acids. Its molecular formula is C400H625N111O115S9 and its approximate mass is 9117.6 Da (CAS 946870-92-4). Mechanistically it acts as an agonist of the IGF-1R receptor and has very low affinity for the IGF-binding proteins (IGFBP), which prolongs its half-life to 20-30 h and increases its relative potency 2-3 times compared with native IGF-1; receptor activation triggers the PI3K/Akt and MAPK signaling pathways. Research-use reagent (RUO) intended for in vitro and preclinical studies.
Mechanism of action
IGF-1 LR3 activates the IGF-1 receptor, promoting cell proliferation, protein synthesis and hypertrophy. Its lower affinity for IGFBPs prolongs its activity.
Mechanism summary
IGF-1R receptor agonist with very low affinity for the IGFBPs. The Glu3->Arg substitution and the N-terminal extension of 13 aa prolong its half-life to 20-30 h and raise its relative potency 2-3 fold relative to native IGF-1, activating the PI3K/Akt and MAPK pathways.
Clinical Studies (6)
- Type I insulin-like growth factor receptor signaling in skeletal muscle regeneration and hypertrophy (Philippou A, et al. · Journal of Musculoskeletal and Neuronal Interactions · 2007) — Review of the role of IGF-1 in skeletal muscle regeneration. PMID 17947802.
- Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency (Francis, et al. · Journal of Molecular Endocrinology · 1992) PMID 1378742.
- Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection (Tomas, et al. · Journal of Endocrinology · 1996) PMID 8708565.
- IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep. (White A, et al. · Am J Physiol Endocrinol Metab · 2025) PMID 39679943.
- Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets. (White A, et al. · J Dev Orig Health Dis · 2023) PMID 37114757.
- Long [R3] insulin-like growth factor-I reduces growth, plasma growth hormone, IGF binding protein-3 and endogenous IGF-I concentrations in pigs. (Dunaiski V, et al. · J Endocrinol · 1997) PMID 9488001.
Warnings
IGF-1 LR3 is a compound exclusively for research use (RUO); the following warnings and handling considerations apply to its use in the laboratory:
- Monitor glucose
- Use with caution
- Diabetes
- Active malignancy
- Pregnancy
Technical data
- CAS
- 946870-92-4
- Molecular formula
- C400H625N111O115S9
- Molecular weight
- 9117.6 Da
- Compound type
- peptide
- Storage
- -20 °C liofilizado; 2-8 °C reconstituido
- Shelf life (lyophilized)
- 18 months
- Shelf life (reconstituted)
- 21 days refrigerated
- Light-sensitive
- Sí
Available for research
IGF-1 LR3 está disponible como reactivo for research (RUO):
Frequently asked questions about IGF-1 LR3
What is IGF-1 LR3?
Long-acting recombinant IGF-1 analogue (Long [Arg3]-IGF-I): arginine at position 3 and an N-terminal extension of 13 aa (83 aa). IGF-1R agonist with low affinity for IGFBP and a half-life of 20-30 h.
What is the mechanism of action of IGF-1 LR3?
IGF-1R receptor agonist with very low affinity for the IGFBPs. The Glu3->Arg substitution and the N-terminal extension of 13 aa prolong its half-life to 20-30 h and raise its relative potency 2-3 fold relative to native IGF-1, activating the PI3K/Akt and MAPK pathways.
What is IGF-1 LR3 researched for?
In preclinical research, IGF-1 LR3 is studied mainly in: Reduction of binding to IGFBPs; Extended half-life (20-30h); Signaling via the IGF-1R receptor. Material exclusively for scientific research.
What are the chemical properties of IGF-1 LR3?
Molecular formula C400H625N111O115S9; molecular weight 9117.6 Da; CAS number 946870-92-4.
How is IGF-1 LR3 stored?
Condiciones de conservación: -20 °C liofilizado; 2-8 °C reconstituido; estabilidad liofilizado: 18 meses; una vez reconstituido: 21 días refrigerado; protéjase de la luz.
What routes of administration are studied for IGF-1 LR3?
In research models the following are described: Subcutaneous, Intramuscular. Use is exclusively for scientific research.