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IGF-1 LR3
1 mg lyophilized powder in a sealed glass vial.
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- Sequence
- 83 residues, IGF-1 with Arg3 and a 13-residue N-terminal extension
- CAS number
- 143045-27-6
- Molecular weight
- 9111.6 g/mol
- Counter-ion
- Stated on the certificate of analysis
- Contents
- IGF-1 LR3 · 1 mg per vial
- Form
- Lyophilized powder, sealed under inert gas
- Storage
- 2–8 °C sealed, protected from light
- Documentation
- Certificate of Analysis per batch, linked via QR
- Delivery
- Ships from our warehouse in Poland within 1–3 working days, tracked, no customs within the EU. Typically 3–5 working days; shipping €9.00, free from €150.
What IGF-1 LR3 is
IGF-1 LR3 (Long R3 IGF-I) is a recombinant analogue of human insulin-like growth factor 1, itself a 70-amino-acid protein. The analogue has 83 residues: the glutamate at position 3 of IGF-1 is replaced by arginine, and a 13-residue extension derived from methionyl porcine growth hormone is added at the N-terminus. These changes reduce its affinity for the IGF-binding proteins that carry IGF-1 in serum. It was developed in Adelaide in the early 1990s and is used mainly as an insulin substitute in serum-free cell-culture media. Being a folded protein with three disulfide bonds rather than a short peptide, it is supplied here as a lyophilized (freeze-dried) powder for laboratory research.
What the research examines
Binding-protein interaction. The 1992 paper introducing the analogue measured its affinity for IGF-binding proteins and for the type 1 IGF receptor in competitive binding assays, and compared protein synthesis and breakdown in cultured rat L6 myoblasts. It reported that reduced binding-protein affinity, rather than receptor affinity, accounted for the difference in activity from native IGF-1.
Rat growth models. Studies in normal and dexamethasone-treated rats compared native IGF-1 with IGF-1 LR3, measuring body-weight gain, nitrogen retention, organ weights and rates of muscle protein synthesis and breakdown. They reported larger changes with the analogue than with IGF-1 at matched exposure, consistent with its weaker binding-protein interaction.
Cell-culture manufacturing. Bioprocess studies examined IGF-1 LR3 as a replacement for insulin in serum-free Chinese hamster ovary cell cultures producing recombinant proteins, measuring cell growth, viability and product yield. This use in defined culture media is the analogue's principal documented application and the reason it is manufactured at scale.
The IGF-1 axis. Reviews of IGF-1 biology describe how binding proteins, receptor signalling and feedback on growth hormone shape IGF-1 activity in the body, and discuss analogues with altered binding-protein affinity in the context of endocrine disorders, atherosclerosis and cancer, where IGF-1 signalling is under investigation.
Published work on IGF-1 LR3 is preclinical: binding assays, cell culture, rodent studies and bioprocess literature. No clinical trial of IGF-1 LR3 has been published. Native IGF-1 (mecasermin) is an approved medicine (Increlex, 2005), but the LR3 analogue is a distinct molecule, and IGF-1 analogues are prohibited by the World Anti-Doping Agency. IGF-1 LR3 is not an approved medicine, and this page makes no claims about effects in humans.
Selected literature
- Francis GL, et al. Journal of Molecular Endocrinology, 1992, original characterisation; binding assays and cell culture. doi:10.1677/jme.0.0080213
- Tomas FM, et al. Biochemical Journal, 1992, rat model. doi:10.1042/bj2820091
- Tomas FM, et al. Journal of Endocrinology, 1993, rat model. doi:10.1677/joe.0.1370413
- Morris AE, Schmid J Biotechnology Progress, 2000, bioprocess cell-culture study. doi:10.1021/bp0000914
- Clemmons DR Nature Reviews Drug Discovery, 2007, review. doi:10.1038/nrd2359
Every reference is listed with its DOI in the research library.
Handling in the laboratory
Store sealed at 2–8 °C for routine use or frozen for long-term storage, protected from light and moisture. Let the vial reach room temperature before opening. See Storage and handling of lyophilized research peptides.
New to research peptides?
What is a research peptide?
A short chain of amino acids produced synthetically for laboratory investigation. Research peptides are sold as chemical reagents to study biological mechanisms; they are not medicines, foods or supplements and are not for human use.
What does "lyophilized" mean?
Freeze-dried. The peptide is supplied as a dry powder, which keeps it stable in storage. It is dissolved in the laboratory before use in an experiment.
How do I verify a batch?
Scan the QR on the vial, or open "Verify a batch" and enter the batch number. The report opens on the independent laboratory's own website, we cannot edit it.
What does the purity figure mean?
The share of the vial's peptide content that is the intended sequence, measured by HPLC. Identity is confirmed separately by mass spectrometry, so both "what" and "how pure" are tested.
How should it be stored?
Sealed vials at 2–8 °C, protected from light. Our storage guide covers handling of opened vials.