IGF-1 LR3

IGF-1 LR3 in brief

IGF-1 LR3 is an 83-residue recombinant analogue of insulin-like growth factor I: arginine replaces the glutamate at position 3, and a 13-residue extension from porcine growth hormone is joined to the N terminus as a refolding and yield device. Both changes sit at the end a binding protein grips rather than the end the receptor reads, so its potency against the parent hormone depends on whether binding proteins are present. Identity is settled by two independent records, the FDA substance registry and the deposited structure, which agree on the sequence and on the three disulfides. One solution NMR structure of the analogue exists, and none with a receptor or a binding protein. It is a culture reagent with no approved use in people, prohibited in sport at all times, and the formula and mass here are computed rather than measured.^{[1,2,3,4,5,6,7,8]}

IGF-1 LR3 regulatory status

No FDA, EMA or Health Canada marketing authorisation for this analogue was found in Drugs@FDA, the EMA medicines database or the Health Canada Drug Product Database (searched November 2026); the approved recombinant IGF-I, mecasermin (approved in the US for growth failure in children with severe primary IGF-I deficiency), is a different molecule. The analogue does hold an FDA substance registry record and an RxNorm ingredient concept, and neither is an approval: both are name records with no product attached. The WADA 2026 Prohibited List names insulin-like growth factor 1 and its analogues under S2.3, growth factors and growth factor modulators, prohibited at all times. The FDA's list of certain bulk drug substances for use in compounding that may present significant safety risks, current as of 22 April 2026, does not name it in either of its category 2 tables or among the withdrawn nominations.^{[9,10,11,8,7,12,13]}

IGF-1 LR3 at a glance

• An 83-residue protein: the 70-residue human insulin-like growth factor I chain with arginine substituted for glutamate at position 3, preceded by the 13-residue extension MFPAMPLSSLFVN. Three disulfides, no lipid, no sugar, no metal, free C terminus.^[2,6,1]
• Both modifications sit at one end of the molecule, and the end they sit at is the one a binding protein grips rather than the one a receptor reads. That separation of surfaces is what the design exploits and is visible in structures of the parent hormone held by binding proteins.^[3,14,15,16]
• Its potency relative to the parent hormone depends on whether binding proteins are present. In cell lines that secrete them the analogue was the more active of the two; in chicken embryo fibroblasts, which secrete none detectably, it was the less active.^[1]
• An experimental structure of the exact analogue exists, PDB 3LRI, by solution NMR. The hormone domain matches earlier structures of the parent; the extension has no settled conformation.^[2,4,17]
• Registry identity is now settled, and it was the page's weakest point. The FDA substance registry holds a protein-class record, UNII M9L22Y19H9, carrying CAS 143045-27-6, a sequence byte-identical to the one above and the same three disulfide links; an RxNorm ingredient concept hangs off it and carries no product. No PubChem compound and no ChEBI or ChEMBL entry was located, which is ordinary for a protein of this size, so the formula and masses below are still computed from the sequence rather than quoted from a measurement.^[7,12,2,6]

What is IGF-1 LR3?

IGF-1 LR3 is a protein-engineering product from the early 1990s. A group in Adelaide was building analogues of insulin-like growth factor I to test one question: whether the apparent activity of the hormone in a culture system is set by how tightly it binds its receptor, or by how much of it the binding proteins in the medium hold back. They expressed several variants in Escherichia coli as fusion proteins and named them by the two things that varied, the residue at position 3 and the presence of an N-terminal extension. Long [Arg3]-IGF-I was one of four, beside Long IGF-I, Long [Gly3]-IGF-I and the authentic hormone, with the earlier truncated des(1-3)IGF-I as comparator.^[1,18,19]

The extension was a manufacturing device rather than an activity one. The authors report that a hydrophobic N-terminal extension helped the reduced, denatured chain refold correctly and gave high yields of folded product, which plain-length growth factors had not. It is borrowed: the initiator methionine plus the first residues of porcine growth hormone, followed by valine and asparagine, two residues that in the original construct also provided the seam at which a longer leader was cut. A later study in yeast produced both the parent and the analogue as xylanase fusions, so the molecule is no longer tied to one expression route.^[1,18,20]

What the molecule became, in practice, is a laboratory reagent. It supports Chinese hamster ovary cells in serum-free medium at far lower concentrations than insulin, it sustained the viability of two production cell lines better than insulin did, and it has been used in place of insulin in human embryonic kidney cultures and in bovine oocyte maturation. It is also a named analyte in sports drug testing, which is where the most careful chemistry on supplied material has been done.^{[5,21,22,23,24]}

Its status is short and worth stating on its own. No regulator has authorised a medicine made of this analogue: Drugs@FDA, the European Medicines Agency medicines database and the Health Canada Drug Product Database return nothing for it, the approved recombinant IGF-I is a different molecule, and the FDA's list of bulk drug substances that may present significant safety risks for compounding does not name it at all. It is prohibited in sport at all times, through the class insulin-like growth factor 1 and its analogues at S2.3 of the World Anti-Doping Agency 2026 Prohibited List. A narrative review of this class places it among compounds sold as research chemicals whose supplied composition is uncertain, and the analytical record bears that out: one case report identified the contents of a sealed product as this analogue carrying a hexahistidine purification tag, and a validated detection method found abundant oxidised forms in products obtained outside legitimate supply.^{[9,10,11,13,8,25,26,24]}

IGF-1 LR3 structure and sequence

Read from the N terminus, the molecule begins with thirteen residues that do not belong to the hormone at all: methionine, phenylalanine, proline, alanine, methionine, proline, leucine, serine, serine, leucine, phenylalanine, valine, asparagine. Then the hormone chain starts, glycine and proline, and at its third position, construct position 16, sits the arginine replacing glutamate. Everything after that is the human sequence, folded by three disulfides in the parent pattern: construct 19 to 61, 31 to 74 and 60 to 65. The extension carries no cysteine, so it hangs off a fold it does not stabilise.^[2,6]

Two independent lines of chemistry agree with that description. A folding study trapped disulfide intermediates by cyanylation, isolating six for the parent and three for the analogue, which is a direct observation that the analogue reaches the same three bonds by a shorter route. A proteolysis study found that pepsin cuts first inside the extension, at the bond between its tenth and eleventh residues, releasing a fragment the authors name for the three residues the cut leaves in front, Phe-Val-Asn, before cutting at four further bonds inside the hormone chain. That cleavage map fits an extension of exactly thirteen residues ending Phe-Val-Asn and no other length.^[27,28]

The three-dimensional view on this page is PDB 3LRI, a solution NMR ensemble of the analogue itself, and it shows a well-formed hormone domain with an ill-defined tail. The hormone part agrees with earlier structures of the parent apart from small changes away from the N terminus, the clearest difference being a substantial reorientation of the first three residues of the hormone chain, which is where the substitution sits. The extension's first seven residues give almost no medium or long range NOEs while the next five form a turn-like element close to the start of the first helix, and many of its amide protons are shielded from solvent without adopting identifiable secondary structure. The ensemble is a set of models consistent with restraints collected at pH 3, and it contains no partner molecule, so it cannot show how either surface is used.^[4,17,2]

Two kinds of number describe this protein's mass and they should not be read as the same thing. The figures above are arithmetic from the sequence, and the three that circulate differ only by how many disulfides are counted as formed: 9117.60 for the reduced chain, about 9,120 in the registry record whose formula corresponds to one bond, and 9111.5 here for the three the structure and the registry's own link list both declare. What published characterisation adds is an apparent mass by gel. A reagent-grade datasheet specifies about 9.1 kDa by SDS-PAGE under reducing conditions, purity above 95 percent by the same method, and a half-maximal effective concentration below 10 ng/ml in a Chinese hamster ovary cell proliferation assay. Those are a manufacturer's specifications rather than results reported in a paper, and a gel resolves to the nearest few hundred daltons, so they corroborate the computed figures without replacing them. The same datasheet states the handling the chemistry predicts: the lyophilised protein specified as stable for six months below -70 degrees C, and once in dilute acid solution for one week at 4 degrees C or three months at -20 degrees C, with a carrier protein advised for longer storage and repeated freezing and thawing avoided. That matters here because methionine oxidation is the first chemical change analytical work on supplied material looks for, and there are three methionines in this chain.^[29,7,2,24]

All residues are L, and the molecule is linear with no cyclisation, no lipidation, no glycosylation and no bound metal. Three intramolecular disulfides hold the fold, and the deposited structure carries the native pattern of the parent hormone: construct positions 19 to 61, 31 to 74 and 60 to 65, which are IGF-I positions 6 to 48, 18 to 61 and 47 to 52. The extension contains no cysteine and takes no part in the disulfide network. Two methionines sit in the extension and one in the hormone chain, and oxidation of methionine is the chemical change analytical work on supplied material looks for first.^[2,6,27,24]

What studies on IGF-1 LR3 show

Each card names the experimental system and what was measured. A result in one system is not evidence about another.

Why a change at one end of the molecule changes its apparent potency

The chemistry of this analogue follows from one geometric fact about the parent hormone: the surface a binding protein holds and the surface the type 1 receptor reads sit on opposite poles of the molecule. The crystal structure of IGF-I with the N-terminal domain of binding protein 5 described an interface of interlaced hydrophobic side chains inside a network of polar contacts, with a solvent-exposed hydrophobic patch on the far side marking the receptor-binding surface. Crystal structures with binding protein 4 fragments then showed how a binding protein closes over the ligand: a rigid disulfide ladder at its N terminus contacts the growth factor and partially covers the residues the receptor needs, and in a ternary complex the C-terminal domain adds to that masking.^[3,14,15]

That the first three residues of the hormone belong to the binding-protein side of the arrangement was established before this molecule existed. Truncating them lowered the half-maximal concentration for protein synthesis in rat myoblasts roughly ninefold while leaving competition for cell-surface binding almost unchanged, and the truncated peptides competed for binding-protein association at least sixty fold less well than the full-length ones; an earlier paper had reported the truncated derivative as about seven times more active in the same assay with no increase in receptor competition. Replacing the glutamate at position 3 with arginine reproduces that by substitution rather than deletion: the substituted peptide bound very poorly to binding protein 2 and slightly less well than the parent to the receptor.^[16,19,18]

Two consequences of that design pull in opposite directions. Where binding proteins are present, less of the molecule is held back and the measured potency rises; where they are not, the small loss of receptor affinity is all that is left and the analogue measures as the weaker molecule. Both halves have been observed: lower activity in chicken embryo fibroblasts in the original report, and reduced receptor competition with lower proliferative activity for the chicken-sequence analogue on turkey muscle cells. In other serum-free systems the two are simply not distinguishable, as in bovine oocyte maturation and in rat neuroretinal cultures, where analogues chosen for deliberately different affinities all behaved alike. The resistance is relative rather than absolute, since intact binding protein 3 suppressed the receptor phosphorylation driven by this analogue much as it did the parent's. The extension has no established role in either interaction: it was introduced to aid refolding, it is the first thing a protease removes, and in the one structure of the analogue it adopts no settled conformation.^{[1,31,22,36,30,28,4]}

What is still unknown about IGF-1 LR3

The formula and both masses here are computed from the sequence rather than measured. The calculation was validated against the 70-residue parent, where it reproduces that hormone's published average mass, and it agrees with the disulfide pattern that both the deposited structure and the FDA substance record declare. But a computed figure is not a measured one, no measured mass for the analogue appeared in the abstracts available, and the only published characterisation of its mass is an apparent 9.1 kDa by gel stated as a reagent specification. What a given preparation contains is a separate and larger unknown: the salt form and counterion of catalogued material are nowhere stated, and the analytical literature has found a purification tag in one sealed product and abundant oxidised forms in others.^{[2,6,7,29,26,24]}

There is one genuine disagreement in the record about the sequence, and it is a property of one deposition rather than of the molecule. The deposited entity of PDB 3LRI reads cysteine at construct position 52, which is position 39 of the hormone chain, where the human sequence, an independent deposition of the parent and the FDA substance record all read proline. The PDB flags it as an engineered mutation, the coordinates carry the cysteine, and it belongs to no disulfide, leaving an unpaired thiol in a molecule whose other six cysteines are all paired. The primary citation describes only the arginine substitution and the thirteen-residue extension, so nothing read here explains it. The sequence above follows the literature and is now corroborated by a second independent record, which is why the identity is recorded as verified while this one view stays one residue away from it.^[2,4,6,37,7]

No design in the record separates the two structural changes. Every organism-level comparison tests the finished analogue against the parent hormone or against other binding-protein-poor variants, so the contribution of the arginine and the contribution of the extension cannot be read apart, and the direction of the result depends on the species: the four studies now carried as experiment cards point different ways in rats, guinea pigs, pigs and mice, and a fifth found the analogue and three other binding-protein-poor variants 2 to 3 times as potent as the parent at lowering plasma glucose in pigs and marmosets, in an order tracking binding-protein affinity. One mechanism inside that is open on its own: the fall in circulating binding protein 3 the pig study reported was not matched by any change in its transcript in liver or kidney, so the authors read that protein level as regulated after translation or as arising in another tissue, and neither was shown.^{[32,33,34,35,38,39]}

What is missing structurally is the part that would matter most. There is no deposited structure of this analogue with the type 1 IGF receptor and none with any binding protein, so the mechanism above is assembled from structures of the parent plus binding and activity measurements on the analogue, and the conformation of the extension in any bound state is unknown. Separately, nothing read here characterises the material sold under this name: one case report identified the contents of a vial as the analogue carrying a hexahistidine purification tag on its C terminus through a Leu-Glu linker, and a validated detection method found abundant oxidised forms in products obtained outside legitimate supply.^{[40,3,14,4,26,24]}

Key papers on IGF-1 LR3

1. 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 GL, Ross M, Ballard FJ, Milner SJ, Senn C, McNeil KA, Wallace JC, King R, Wells JR (1992), Journal of Molecular Endocrinology · Recombinant production with cell assays and binding measurements

   The paper that made the molecule and named it, and the one that frames the whole question: potency measured with and without binding proteins in the medium.

2. Solution structure and backbone dynamics of long-[Arg(3)]insulin-like growth factor-I.

   Laajoki LG, Francis GL, Wallace JC, Carver JA, Keniry MA (2000), The Journal of Biological Chemistry · Solution NMR structure with backbone dynamics

   The only structure of the exact molecule, and the source of everything defensible about its shape and its flexibility.

3. A key functional role for the insulin-like growth factor 1 N-terminal pentapeptide.

   Bagley CJ, May BL, Szabo L, McNamara PJ, Ross M, Francis GL, Ballard FJ, Wallace JC (1989), The Biochemical Journal · Truncation series with bioassay and competition binding

   The pre-history. It establishes that the first three residues of the hormone are a binding-protein determinant, with the potency and binding numbers side by side.

4. The interaction of insulin-like growth factor-I with the N-terminal domain of IGFBP-5.

   Zesławski W, Beisel HG, Kamionka M, Kalus W, Engh RA, Huber R, Lang K, Holak TA (2001), The EMBO Journal · Crystal structure of the parent with a binding protein domain

   The structural reason the design is possible at all: a binding protein grips one pole of the hormone and the receptor reads the other.

5. Effect of IGFBP-3 on IGF- and IGF-analogue-induced insulin-like growth factor-I receptor (IGFIR) signalling.

   Devi GR, Graham DL, Oh Y, Rosenfeld RG (2001), Growth Hormone & IGF Research · Receptor phosphorylation assay

   The most useful corrective. Binding-protein resistance is relative, and in this assay intact binding protein 3 suppressed the analogue's receptor signal much as it did the parent's.

6. Detection of LongR(3) -IGF-I, Des(1-3)-IGF-I, and R(3) -IGF-I using immunopurification and high resolution mass spectrometry for antidoping purposes.

   Mongongu C, Coudoré F, Domergue V, Ericsson M, Buisson C, Marchand A (2021), Drug Testing and Analysis · Immunopurification with high-resolution mass spectrometry

   The careful modern chemistry: separate identification of the three analogues, characterisation of N-terminal degradation products, and a direct look at what unregulated products contain.

7. Design and characterisation of long-R3-insulin-like growth factor-I muteins which show resistance to pepsin digestion.

   Bryant KJ, Read LC, Forsberg G, Wallace JC (1996), Growth Factors · Proteolysis kinetics with site-directed muteins

   Read it for the cleavage map, which locates the extension's residues independently of any sequence record.

8. LONG-(ARG3)INSULIN-LIKE GROWTH FACTOR-I (UNII M9L22Y19H9)

   U.S. Food and Drug Administration; National Center for Advancing Translational Sciences (2026), Global Substance Registration System (GSRS) · Database record

   The registry record, and the thing to read if the identifiers on this page look thin. It carries the CAS number, the exact 83-residue sequence and the three disulfide links, and its own listed formula is one disulfide short of the links it declares, which is how the three circulating masses for this molecule come apart.

References

1. 1.Francis GL, Ross M, Ballard FJ, Milner SJ, Senn C, McNeil KA, Wallace JC, King R, Wells JR. (1992). 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. Journal of Molecular Endocrinology. 8:213-23. doi:10.1677/jme.0.0080213 · abstract only
2. 2.RCSB Protein Data Bank. (2000). PDB 3LRI: Solution structure and backbone dynamics of long-[Arg(3)]insulin-like growth factor-I. RCSB Protein Data Bank. doi:10.2210/pdb3LRI/pdb · database record
3. 3.Zesławski W, Beisel HG, Kamionka M, Kalus W, Engh RA, Huber R, Lang K, Holak TA. (2001). The interaction of insulin-like growth factor-I with the N-terminal domain of IGFBP-5. The EMBO Journal. 20:3638-44. doi:10.1093/emboj/20.14.3638 · abstract only
4. 4.Laajoki LG, Francis GL, Wallace JC, Carver JA, Keniry MA. (2000). Solution structure and backbone dynamics of long-[Arg(3)]insulin-like growth factor-I. The Journal of Biological Chemistry. 275:10009-15. doi:10.1074/jbc.275.14.10009 · abstract only
5. 5.Morris AE, Schmid J. (2000). Effects of insulin and LongR(3) on serum-free Chinese hamster ovary cell cultures expressing two recombinant proteins. Biotechnology Progress. 16:693-7. doi:10.1021/bp0000914 · abstract only
6. 6.UniProt Consortium. UniProtKB P05019 (IGF1_HUMAN): Insulin-like growth factor I, Homo sapiens. UniProtKB. source · database record
7. 7.U.S. Food and Drug Administration; National Center for Advancing Translational Sciences. (2026). LONG-(ARG3)INSULIN-LIKE GROWTH FACTOR-I (UNII M9L22Y19H9). Global Substance Registration System (GSRS). source · database record
8. 8.World Anti-Doping Agency. (2025). World Anti-Doping Code International Standard: Prohibited List 2026. World Anti-Doping Agency. source · full text read
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12. 12.U.S. National Library of Medicine. RxNorm concept RXCUI 1809244, long-(ARG3)insulin-like growth factor-I. RxNorm, read through the RxNav REST service. source · database record
13. 13.U.S. Food and Drug Administration. (2026). Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 22 April 2026). U.S. Food and Drug Administration. source · full text read
14. 14.Sitar T, Popowicz GM, Siwanowicz I, Huber R, Holak TA. (2006). Structural basis for the inhibition of insulin-like growth factors by insulin-like growth factor-binding proteins. Proceedings of the National Academy of Sciences of the United States of America. 103:13028-33. doi:10.1073/pnas.0605652103 · abstract only
15. 15.Carrick FE, Hinds MG, McNeil KA, Wallace JC, Forbes BE, Norton RS. (2005). Interaction of insulin-like growth factor (IGF)-I and -II with IGF binding protein-2: mapping the binding surfaces by nuclear magnetic resonance. Journal of Molecular Endocrinology. 34:685-98. doi:10.1677/jme.1.01756 · abstract only
16. 16.Bagley CJ, May BL, Szabo L, McNamara PJ, Ross M, Francis GL, Ballard FJ, Wallace JC. (1989). A key functional role for the insulin-like growth factor 1 N-terminal pentapeptide. The Biochemical Journal. 259:665-71. doi:10.1042/bj2590665 · abstract only
17. 17.Laajoki LG, Le Breton E, Shooter GK, Wallace JC, Francis GL, Carver JA, Keniry MA. (1997). Secondary structure determination of 15N-labelled human Long-[Arg-3]-insulin-like growth factor 1 by multidimensional NMR spectroscopy. FEBS Letters. 420:97-102. doi:10.1016/s0014-5793(97)01496-8 · abstract only
18. 18.King R, Wells JR, Krieg P, Snoswell M, Brazier J, Bagley CJ, Wallace JC, Ballard FJ, Ross M, Francis GL. (1992). Production and characterization of recombinant insulin-like growth factor-I (IGF-I) and potent analogues of IGF-I, with Gly or Arg substituted for Glu3, following their expression in Escherichia coli as fusion proteins. Journal of Molecular Endocrinology. 8:29-41. doi:10.1677/jme.0.0080029 · abstract only
19. 19.Ballard FJ, Francis GL, Ross M, Bagley CJ, May B, Wallace JC. (1987). Natural and synthetic forms of insulin-like growth factor-1 (IGF-1) and the potent derivative, destripeptide IGF-1: biological activities and receptor binding. Biochemical and Biophysical Research Communications. 149:398-404. doi:10.1016/0006-291x(87)90380-9 · abstract only
20. 20.Lu Z, Liu N, Huang H, Wang Y, Tu T, Qin X, Wang X, Zhang J, Su X, Tian J, Bai Y, Luo H, Yao B, Zhang H. (2023). Recombinant expression of IGF-1 and LR3 IGF-1 fused with xylanase in Pichia pastoris. Applied Microbiology and Biotechnology. 107:4543-4551. doi:10.1007/s00253-023-12606-0 · abstract only
21. 21.Voorhamme D, Yandell CA. (2006). LONG R3IGF-I as a more potent alternative to insulin in serum-free culture of HEK293 cells. Molecular Biotechnology. 34:201-4. doi:10.1385/mb:34:2:201 · abstract only
22. 22.Araujo MS, Guastali MD, Paulini F, Silva AN, Tsunemi MH, Fontes PK, Castilho ACS, Landim-Alvarenga FC. (2020). Molecular and cellular effects of insulin-like growth factor-1 and LongR3-IGF-1 on in vitro maturation of bovine oocytes: comparative study. Growth Hormone & IGF Research. 55:101357. doi:10.1016/j.ghir.2020.101357 · abstract only
23. 23.Thomas A, Walpurgis K, Tretzel L, Brinkkötter P, Fichant E, Delahaut P, Schänzer W, Thevis M. (2015). Expanded test method for peptides >2 kDa employing immunoaffinity purification and LC-HRMS/MS. Drug Testing and Analysis. 7:990-8. doi:10.1002/dta.1868 · abstract only
24. 24.Mongongu C, Coudoré F, Domergue V, Ericsson M, Buisson C, Marchand A. (2021). Detection of LongR(3) -IGF-I, Des(1-3)-IGF-I, and R(3) -IGF-I using immunopurification and high resolution mass spectrometry for antidoping purposes. Drug Testing and Analysis. 13:1256-1269. doi:10.1002/dta.3016 · abstract only
25. 25.Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchała M. (2026). The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Frontiers in Endocrinology. 17:1822475. doi:10.3389/fendo.2026.1822475 · abstract only
26. 26.Kohler M, Thomas A, Walpurgis K, Terlouw K, Schänzer W, Thevis M. (2010). Detection of His-tagged Long-R³-IGF-I in a black market product. Growth Hormone & IGF Research. 20:386-90. doi:10.1016/j.ghir.2010.07.001 · abstract only
27. 27.Yang Y, Wu J, Watson JT. (1999). Probing the folding pathways of long R(3) insulin-like growth factor-I (LR(3)IGF-I) and IGF-I via capture and identification of disulfide intermediates by cyanylation methodology and mass spectrometry. The Journal of Biological Chemistry. 274:37598-604. doi:10.1074/jbc.274.53.37598 · abstract only
28. 28.Bryant KJ, Read LC, Forsberg G, Wallace JC. (1996). Design and characterisation of long-R3-insulin-like growth factor-I muteins which show resistance to pepsin digestion. Growth Factors. 13:261-72. doi:10.3109/08977199609003227 · abstract only
29. 29.GenScript Biotech Corporation. (2026). LR3-IGF-I, Human (Receptor Grade), catalogue product datasheet. GenScript product datasheet. source · full text read
30. 30.Devi GR, Graham DL, Oh Y, Rosenfeld RG. (2001). Effect of IGFBP-3 on IGF- and IGF-analogue-induced insulin-like growth factor-I receptor (IGFIR) signalling. Growth Hormone & IGF Research. 11:231-9. doi:10.1054/ghir.2001.0231 · abstract only
31. 31.Pesall JE, McFarland DC, McMurtry JP, Clapper JA, Francis GL, Gilkerson KK. (2001). The effect of insulin-like growth factor analogs on turkey satellite cell and embryonic myoblast proliferation. Poultry Science. 80:944-8. doi:10.1093/ps/80.7.944 · abstract only
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33. 33.Conlon MA, Tomas FM, Owens PC, Wallace JC, Howarth GS, Ballard FJ. (1995). Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig. The Journal of Endocrinology. 146:247-53. doi:10.1677/joe.0.1460247 · abstract only
34. 34.Dunaiski V, Dunshea FR, Walton PE, Goddard C. (1997). Long [R3] insulin-like growth factor-I reduces growth, plasma growth hormone, IGF binding protein-3 and endogenous IGF-I concentrations in pigs. The Journal of Endocrinology. 155:559-65. doi:10.1677/joe.0.1550559 · abstract only
35. 35.Engel MG, Narayan S, Cui MH, Branch CA, Zhang X, Gandy SE, Ehrlich M, Huffman DM. (2025). Intranasal long R3 insulin-like growth factor-1 treatment promotes amyloid plaque remodeling in cerebral cortex but fails to preserve cognitive function in male 5XFAD mice. Journal of Alzheimer's Disease. 103:113-126. doi:10.1177/13872877241299056 · abstract only
36. 36.Seigel GM, Chiu L, Paxhia A. (2000). Inhibition of neuroretinal cell death by insulin-like growth factor-1 and its analogs. Molecular Vision. 6:157-63. PMID 10973501 · abstract only
37. 37.RCSB Protein Data Bank. (2001). PDB 1H59: Complex of IGFBP-5 with IGF-I. RCSB Protein Data Bank. doi:10.2210/pdb1H59/pdb · database record
38. 38.Tomas FM, Walton PE, Dunshea FR, Ballard FJ. (1997). IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeys. The Journal of Endocrinology. 155:377-86. doi:10.1677/joe.0.1550377 · abstract only
39. 39.Dunaiski V, Dunshea FR, Walton PE, Goddard C. (2002). Short-term infusion of LongR(3) insulin-like growth factor (IGF)-I decreases hepatic IGF-I mRNA but not IGF binding protein-3 mRNA expression in pigs. General and Comparative Endocrinology. 126:221-8. doi:10.1006/gcen.2002.7796 · abstract only
40. 40.Zhang X, Yu D, Sun J, Wu Y, Gong J, Li X, Liu L, Liu S, Liu J, Wu Y, Li D, Ma Y, Han X, Zhu Y, Wu Z, Wang Y, Ouyang Q, Wang T. (2020). Visualization of Ligand-Bound Ectodomain Assembly in the Full-Length Human IGF-1 Receptor by Cryo-EM Single-Particle Analysis. Structure. 28:555-561.e4. doi:10.1016/j.str.2020.03.007 · abstract only
41. 41.Flint DJ, Tonner E, Beattie J, Gardner M. (1994). Several insulin-like growth factor-I analogues and complexes of insulin-like growth factors-I and -II with insulin-like growth factor-binding protein-3 fail to mimic the effect of growth hormone upon lactation in the rat. The Journal of Endocrinology. 140:211-6. doi:10.1677/joe.0.1400211 · abstract only
42. 42.UniProt Consortium. UniProtKB P01248 (SOMA_PIG): Somatotropin, Sus scrofa. UniProtKB. source · database record
43. 43.Harvey MD, Banks PR. (2003). Site-specific fluorescent derivatization and liquid chromatographic-mass spectrometric characterization of long R(3) IGF-I for bioanalytical applications. Journal of Chromatography B. 793:115-25. doi:10.1016/s1570-0232(03)00369-6 · abstract only