Editing Insulin-like growth factor 1 (section)

{{Short description|Protein found in humans}}
{{Use dmy dates|date=December 2021}}
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{{Infobox gene}}

'''Insulin-like growth factor 1''' ('''IGF-1'''), also called '''somatomedin C''', is a [[hormone]] similar in [[tertiary structure|molecular structure]] to [[insulin]] which plays an important role in childhood growth, and has [[Anabolism|anabolic]] effects in adults.<ref>{{cite journal | vauthors = Tahimic CG, Wang Y, Bikle DD | title = Anabolic effects of IGF-1 signaling on the skeleton | journal = Frontiers in Endocrinology | volume = 4 | pages = 6 | date = 2013 | pmid = 23382729 | pmc = 3563099 | doi = 10.3389/fendo.2013.00006 | doi-access = free }}</ref> In the 1950s IGF-1 was called "[[sulfation]] factor" because it stimulated sulfation of cartilage in vitro,<ref>{{cite journal | vauthors = Salmon WD, Daughaday WH | title = A hormonally controlled serum factor which stimulates sulfate incorporation by cartilage in vitro | journal = The Journal of Laboratory and Clinical Medicine | volume = 49 | issue = 6 | pages = 825–836 | date = June 1957 | pmid = 13429201 }}</ref> and in the 1970s due to its effects it was termed "nonsuppressible insulin-like activity" (NSILA).<ref>{{cite journal | vauthors = Meuli C, Zapf J, Froesch ER | title = NSILA-carrier protein abolishes the action of nonsuppressible insulin-like activity (NSILA-S) on perfused rat heart | journal = Diabetologia | volume = 14 | issue = 4 | pages = 255–259 | date = April 1978 | pmid = 640301 | doi = 10.1007/BF01219425 }}</ref>

<!-- Structure -->IGF-1 is a [[protein]] that in humans is [[Genetic code|encoded]] by the ''IGF1'' [[gene]].<ref name="pmid2982726">{{cite journal | vauthors = Höppener JW, de Pagter-Holthuizen P, Geurts van Kessel AH, Jansen M, Kittur SD, Antonarakis SE, Lips CJ, Sussenbach JS | title = The human gene encoding insulin-like growth factor I is located on chromosome 12 | journal = Human Genetics | volume = 69 | issue = 2 | pages = 157–160 | year = 1985 | pmid = 2982726 | doi = 10.1007/BF00293288 | s2cid = 5825276 }}</ref><ref name="pmid6358902">{{cite journal | vauthors = Jansen M, van Schaik FM, Ricker AT, Bullock B, Woods DE, Gabbay KH, Nussbaum AL, Sussenbach JS, Van den Brande JL | title = Sequence of cDNA encoding human insulin-like growth factor I precursor | journal = Nature | volume = 306 | issue = 5943 | pages = 609–611 | year = 1983 | pmid = 6358902 | doi = 10.1038/306609a0 | s2cid = 4336584 | bibcode = 1983Natur.306..609J }}</ref> IGF-1 consists of 70 [[amino acid]]s in a single chain with three [[intramolecular reaction|intramolecular]] [[disulfide bridges]]. IGF-1 has a [[molecular weight]] of 7,649 [[Dalton (unit)|dalton]]s.<ref name="pmid632300">{{cite journal | vauthors = Rinderknecht E, Humbel RE | title = The amino acid sequence of human insulin-like growth factor I and its structural homology with proinsulin | journal = The Journal of Biological Chemistry | volume = 253 | issue = 8 | pages = 2769–2776 | date = April 1978 | pmid = 632300 | doi = 10.1016/S0021-9258(17)40889-1 | doi-access = free }}</ref> In dogs, an ancient [[mutation]] in IGF1 is the primary cause of the [[Toy dog|toy]] [[phenotype]].<ref>{{cite journal | vauthors = Callaway E | title = Big dog, little dog: mutation explains range of canine sizes | journal = Nature | volume = 602 | issue = 7895 | pages = 18 | date = February 2022 | pmid = 35087254 | doi = 10.1038/d41586-022-00209-0 | s2cid = 246359754 | bibcode = 2022Natur.602...18C }}</ref>

<!-- Synthesis -->IGF-1 is produced primarily by the [[liver]]. Production is stimulated by [[growth hormone]] (GH). Most of IGF-1 is bound to one of 6 binding proteins (IGF-BP). IGFBP-1 is regulated by insulin. IGF-1 is produced throughout life; the highest rates of IGF-1 production occur during the [[Adolescence#Growth spurt|pubertal growth spurt]].<ref name="pmid28076448">{{cite journal | vauthors = Decourtye L, Mire E, Clemessy M, Heurtier V, Ledent T, Robinson IC, Mollard P, Epelbaum J, Meaney MJ, Garel S, Le Bouc Y, Kappeler L | title = IGF-1 Induces GHRH Neuronal Axon Elongation during Early Postnatal Life in Mice | journal = PLOS ONE | volume = 12 | issue = 1 | pages = e0170083 | date = 2017 | pmid = 28076448 | pmc = 5226784 | doi = 10.1371/journal.pone.0170083 | doi-access = free | bibcode = 2017PLoSO..1270083D }}</ref> The lowest levels occur in infancy and old age.<ref>{{cite journal | vauthors = Suwa S, Katsumata N, Maesaka H, Tokuhiro E, Yokoya S | title = Serum insulin-like growth factor I (somatomedin-C) level in normal subjects from infancy to adulthood, pituitary dwarfs and normal variant short children | journal = Endocrinologia Japonica | volume = 35 | issue = 6 | pages = 857–864 | date = December 1988 | pmid = 3250861 | doi = 10.1507/endocrj1954.35.857 | s2cid = 6965802 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Landin-Wilhelmsen K, Wilhelmsen L, Lappas G, Rosén T, Lindstedt G, Lundberg PA, Bengtsson BA | title = Serum insulin-like growth factor I in a random population sample of men and women: relation to age, sex, smoking habits, coffee consumption and physical activity, blood pressure and concentrations of plasma lipids, fibrinogen, parathyroid hormone and osteocalcin | journal = Clinical Endocrinology | volume = 41 | issue = 3 | pages = 351–357 | date = September 1994 | pmid = 7955442 | doi = 10.1111/j.1365-2265.1994.tb02556.x | s2cid = 24346368 }}</ref><!-- Health effects -->

Low IGF-1 levels are associated with [[cardiovascular disease]], while high IGF-1 levels are associated with [[cancer]]. Mid-range IGF-1 levels are associated with the lowest [[Mortality rate|mortality]].

<!-- Analogs and metabolites -->A synthetic analog of IGF-1, [[mecasermin]], is used for the treatment of [[growth failure]] in children with severe IGF-1 deficiency.<ref name="pmid18481900">{{cite journal | vauthors = Keating GM | title = Mecasermin | journal = BioDrugs | volume = 22 | issue = 3 | pages = 177–188 | year = 2008 | pmid = 18481900 | doi = 10.2165/00063030-200822030-00004 }}</ref> [[Cyclic glycine-proline]] (cGP) is a metabolite of hormone insulin-like growth factor-1 (IGF-1). It has a cyclic structure, lipophilic nature, and is enzymatically stable which makes it a more favourable candidate for manipulating the binding-release process between IGF-1 and its binding protein, thereby normalising IGF-1 function.<ref>{{cite journal | vauthors = Guan J, Li F, Kang D, Anderson T, Pitcher T, Dalrymple-Alford J, Shorten P, Singh-Mallah G | title = Cyclic Glycine-Proline (cGP) Normalises Insulin-Like Growth Factor-1 (IGF-1) Function: Clinical Significance in the Ageing Brain and in Age-Related Neurological Conditions | journal = Molecules | volume = 28 | issue = 3 | pages = 1021 | date = January 2023 | pmid = 36770687 | pmc = 9919809 | doi = 10.3390/molecules28031021 | doi-access = free }}</ref>