IGF1, Human, HEK293 Cells,Tag Free

Insulin-like Growth Factor I (IGF-I) , also known as Somatomedin C, is the dominant effector of Growth Hormone (GH) and is structurally homologous to Proinsulin. Human IGF-I is synthesized as two precursor isoforms with N- and alternative C-terminal propeptides (1). These isoforms are differentially expressed by various tissues (1). The 7.6 kDa mature IGF-I is identical between isoforms and is generated by proteolytic removal of the N- and C-terminal regions. Mature human IGF-I shares 94% and 96% amino acid (aa) sequence identity with the mouse and rat orthologs, respectively (2). GH stimulates

the production of IGF-I in most tissues (3). Hepatocytes produce circulating IGF-I, while local IGF-I is produced by many other tissues in which it has

paracrine effects (1). IGF-I induces the proliferation, migration, and differentiation of a wide variety of cell types during development and postnatally (4, 5).

IGF-I regulates glucose, fatty acid, and protein metabolism, steroid hormone activity, and cartilage and bone metabolism (6-11). It plays an important role

in muscle regeneration and tumor progression (1, 12, 13). IGF-I binds IGF-I R, IGF-II R, and the Insulin Receptor, although its effects are mediated primarily by IGF-I R (14). IGF-I also binds with strong affinity to IGF binding proteins (IGFBPs), which regulate the availability and biological activities of IGF-I (15, 16).Long R3 IGF-I (LR3 IGF-I) is a 9.2 kDa synthetic analog of IGF-I that is generated by modifying the aa sequence for mature human IGF-I. These

modifications include the substitution of an Arg for Glu at position 3 of the mature IGF-1 sequence and the addition of a thirteen aa N-terminal extension, which is derived from methionyl porcine Growth Hormone (17). 

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2. Sandberg-Nordqvist, A.C. et al. (1992) Brain Res. Mol. Brain Res. 12:275.

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4. Guvakova, M.A. (2007) Int. J. Biochem. Cell Biol. 39:890.

5. Sadagurski, M. and M.F. White (2013) Endocrinol. Metab. Clin. North Am. 42:127.

6. Clemmons, D.R. (2006) Curr. Opin. Pharmacol. 6:620.

7. Bluher, S. et al. (2005) Best Pract. Res. Clin. Endocrinol. Metab. 19:577.

8. Garcia-Segura, L.M. et al. (2006) Neuroendocrinology 84:275.

9. Malemud, C.J. (2007) Clin. Chim. Acta 375:10.

10. Ling, P.R. et al. (1995) Am. J. Clin. Nutr. 61:116.

11. Sheng, M.H. et al. (2014) J. Bone Metab. 21:41.

12. Samani, A.A. et al. (2007) Endocrine Rev. 28:20.

13. Gallagher, E.J. et al. (2010) Endocr. Pract. 16:864.

14. LeRoith, D. and S. Yakar (2007) Nat. Clin. Pract. Endocrinol. Metab. 3:302.

15. Denley, A. et al. (2005) Cytokine Growth Factor Rev. 16:421.

16. Duan, C. and Q. Xu (2005) Gen. Comp. Endocrinol. 142:44.

17. Francis, G.L. et al. (1992) J. Mol. Endocrinol. 8:213.