Abstract
The GH/IGF-I system plays a well-known hormonal role and its effects, mainly anabolic and insulin-sensitizing, are mediated through endocrine as well as paracrine/autocrine mechanisms. This system includes the binding proteins, namely GH binding proteins and IGF-I binding proteins (IGFBP). As expected, this axis plays a key role in organism modification in consequence of a physical exercise. Physical activity, training, and exercise capacity chiefly involve anabolism process modifications of various tissues, in particular muscular adjustments. Numerous investigators found a correlation among the level of exercise tolerance, muscle strength or walking speed and IGF-I/IGFBP-3 concentrations. However, also inverse and absent correlations between circulating IGF-I concentrations and acute or chronic exercise responses have been reported. IGF-I is generally accepted as an important GH mediator with metabolic effects, through both endocrine and paracrine or autocrine mechanisms. GH is the main regulator of the hepatic synthesis of IGF-I and IGFBP-3, which is the most abundant IGF carrier in human plasma. Recently, it has been shown that the physical exercise stimulatory impact on skeletal muscles is mediated through an increased local IGF-I synthesis with an IGFPB involvement. An absent association of exercise performance and circulating IGF-I may indicate that exercise will exert muscle strength by predominately locally derived paracrine or autocrine mediators rather than endocrine circulating IGF-I. The present review considers the general aspects of the IGF/IGFPB system and the role of the IGF/IGFPB system in relation to physical exercise (type, duration, etc.) taking into account the training aspects.
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Annunziata M, Granata R, Ghigo E. The IGF system. Acta Diabetol 2011, 48: 1–9.
Matheny RW Jr, Nindl BC, Adamo ML. Minireview: Mechano-growth factor: a putative product of IGF-I gene expression involved in tissue repair and regeneration. Endocrinology 2010, 151: 865–75.
Hennessy BT, Smith DL, Ram PT, Lu Y, Mills GB. Exploiting the PI3K/AKT pathway for cancer drug discovery. Nat Rev Drug Discov 2005, 4: 988–1004.
Wilson EM, Rotwein P. Control of MyoD function during initiation of muscle differentiation by an autocrine signaling pathway activated by insulin-like growth factor-II. J Biol Chem 2006, 281: 29962–71.
Wilson EM, Hsieh MM, Rotwein P. Autocrine growth factor signalling by insulin-like growth factor-II mediates MyoD-stimulated myocyte maturation. J Biol Chem 2003, 278: 41109–13.
Chao W, D’Amore PA. IGF2: epigenetic regulation and role in development and disease. Cytokine Growth Factor Rev 2008, 19: 111–20.
Wheatcroft SB, Kearney MT. IGF-dependent and IGF-independent actions of IGF-binding protein-1 and -2: implications for metabolic homeostasis. Trends Endocrinol Metab 2009, 20: 152–62.
Jones JI, Gockerman A, Busby WH Jr, Wright G, Clemmons DR. Insulin-like growth factor binding protein 1 stimulates cell migration and binds to the alpha 5 beta 1 integrin by means of its Arg-Gly-Asp sequence. Proc Natl Acad Sci U S A 1993, 15: 10553–7.
Guler HP, Zapf J, Schmid C, Froesch ER. Insulin-like growth factors I and II in healthy man. Estimations of half-lives and production rates. Acta Endocrinol (Copenh) 1989, 121: 753–8.
Ruan W, Lai M. Insulin-like growth factor binding protein: a possible marker for the metabolic syndrome? Acta Diabetol 2010, 47: 5–14.
Rajaram S, Baylink DJ, Mohan S. Insulin-like growth factor-binding proteins in serum and other biological fluids: regulation and functions. Endocr Rev 1997, 18: 801–31.
Govoni KE, Baylink DJ, Mohan S. The multi-functional role of insulin-like growth factor binding proteins in bone. Pediatr Nephrol 2005, 20: 261–8.
Yakar S, Rosen CJ, Bouxsein ML, et al. Serum complexes of insulinlike growth factor-1 modulateskeletal integrity and carbohydrate metabolism. FASEB J 2009, 23: 709–19.
Parker A, Rees C, Clarke J, Busby WH Jr, Clemmons DR. Binding of insulin-like growth factor (IGF)-binding protein-5 to smooth-muscle cell extracellular matrix is a major determinant of the cellular response to IGF-I. Mol Biol Cell 1998, 9: 2383–92.
Bunn R.C, Fowlkes JL. Insulin-like growth factor binding protein proteolysis. Trends Endocrinol Metab 2003, 14: 176–81.
Duan C, Xu Q. Roles of insulin-like growth factor (IGF) binding proteins in regulating IGF actions. Gen Comp Endocrinol 2005, 142: 44–52.
Mohan S, Baylink DJ, Pettis JL. Insulin-like growth factor (IGF)-binding proteins in serum—do they have additional roles besides modulating the endocrine IGF actions? J Clin Endocrinol Metab 1996, 81: 3817–20.
Jones JI, Clemmons DR. Insulin-like growth factors and their binding proteins: biological actions. Endocr Rev 1995, 16: 3–34.
Coverley J.A, Baxter RC. Phosphorylation of insulin-like growth factor binding proteins. Mol Cell Endocrinol 1997, 128: 1–5.
Xu Q, Li S, Zhao Y, Maures TJ, Yin P, Duan C. Evidence that IGF binding protein-5 functions as a ligand-independent transcriptional regulator in vascular smooth muscle cells. Circ Res 2004, 94: E46–54.
Yamada PM, Lee KW. Perspectives in mammalian IGFBP-3 biology: local vs. systemic action. Am J Physiol Cell Physiol 2009, 296: C954–76.
Chesik D, De Keyser J, Bron R, Fuhler GM. Insulin-like growth factor binding protein-1 activates integrin-mediated intracellular signaling and migration in oligodendrocytes. J Neurochem 2010, 113: 1319–30.
Backeljauw P, Bang P, Dunger DB, Juul A, Le Bouc Y, Rosenfeld R. Insulin-like growth factor-I in growth and metabolism. J Pediatr Endocrinol Metab 2010, 23: 3–16.
Thissen JP, Ketelslegers JM, Underwood LE. Nutritional regulation of the insulin-like growth factors. Endocr Rev 1994, 15: 80–101.
Lieberman SA, Butterfield GE, Harrison D, Hoffman AR. Anabolic effects of recombinant insulin-like growth factor-I in cachectic patients with the acquired immunodeficiency syndrome. J Clin Endocrinol Metab 1994, 78: 404–10.
Gianotti L, Broglio F, Ramunni J, et al. The activity of GH/IGF-I axis in anorexia nervosa and in obesity: a comparison with normal subjects and patients with hypopituitarism or critical illness. Eat Weight Disord 1998, 3: 64–70.
Schneider HJ, Saller B, Klotsche J, et al. Opposite associations of age-dependent insulin-like growth factor-I standard deviation scores with nutritional state in normal weight and obese subjects. Eur J Endocrinol 2006, 154: 699–706.
Elgin RG, Busby WH Jr, Clemmons DR. An insulin-like growth factor (IGF) binding protein enhances the biologic response to IGF-I. Proc Natl Acad Sci U S A 1987, 84: 3254–8.
Burch WM, Correa J, Shively JE, Powell DR. The 25-kilodalton insulin-like growth factor (IGF)-binding protein inhibits both basal and IGF-I-mediated growth of chick embryo pelvic cartilage in vitro. J Clin Endocrinol Metab 1990, 70: 173–80.
Kajantie E, Dunkel L, Rutanen EM, et al. IGF-I, IGF binding protein (IGFBP)-3, phosphoisoforms of IGFBP-1, and postnatal growth in very low birth weight infants. J Clin Endocrinol Metab 2002, 87: 2171–9.
Jones JI, D’Ercole AJ, Camacho-Hubner C, Clemmons DR. Phosphorylation of insulin-like growth factor (IGF)-binding protein 1 in cell culture and in vivo: effects on affinity for IGF-I. Proc Natl Acad Sci USA 1991, 88: 7481–5.
Crossey PA, Jones JS, Miell JP. Dysregulation of the insulin/IGF binding protein-1 axis in transgenic mice is associated with hyperinsulinemia and glucose intolerance. Diabetes 2000, 49: 457–65.
Rajkumar K, Krsek M, Dheen ST, Murphy LJ. Impaired glucose homeostasis in insulin-like growth factor binding protein-1 transgenic mice. J Clin Invest 1996, 98: 1818–25.
Katz LE, DeLeón DD, Zhao H, Jawad AF. Free and total insulin like growth factor (IGF)-I levels decline during fasting: relationships with insulin and IGF-binding protein-1. J Clin Endocrinol Metab 2002, 87: 2978–83.
Clemmons DR, Snyder DK, Busby WH Jr. Variables controlling the secretion of insulin-like growth factor binding protein-2 in normal human subjects. J Clin Endocrinol Metab 1991, 73: 727–33.
Clemmons DR. Role of insulin-like growth factor binding proteins in controlling IGF actions. Mol Cell Endocrinol 1998, 140: 19–24.
Arai T, Busby W Jr, Clemmons DR. Binding of insulin-like growth factor (IGF) I or II to IGF-binding protein-2 enables it to bind to heparin and extracellular matrix. Endocrinology 1996, 137: 4571–5.
Arafat AM, Weickert MO, Frystyk J, et al. The role of insulin-like growth factor (IGF) binding protein-2 in the insulin-mediated decrease in IGF-I bioactivity. J Clin Endocrinol Metab 2009, 94: 5093–101.
Lukanova A, Söderberg S, Stattin P, et al. Nonlinear relationship of insulin-like growth factor (IGF)-I and IGF-I/IGF-binding protein-3 ratio with indices of adiposity and plasma insulin concentrations (Sweden). Cancer Causes Control 2002, 13: 509–51.
Heald AH, Kaushal K, Siddals KW, Rudenski AS, Anderson SG, Gibson JM. Insulin-like growth factor binding protein-2 (IGFBP-2) is a marker for the metabolic syndrome. Exp Clin Endocrinol Diabetes 2006, 114: 371–6.
Frystyk J, Skjaerbaek C, Vestbo E, Fisker S, Orskov H. Circulating levels of free insulin-like growth factors in obese subjects: the impact of type 2 diabetes. Diabetes Metab Res Rev 1999, 15: 314–22.
Zimmermann EM, Li L, Hoyt EC, Pucilowska JB, Lichtman S, Lund, PK. Cell-specific localization of insulin-like growth factor binding protein mRNAs in rat liver. Am J Physiol Gastrointest Liver Physiol 2000, 278: G447–57.
Jogie-Brahim S, Feldman D, Oh Y. Unraveling insulin-like growth factor binding protein-3 actions in human disease. Endocr Rev 2009, 30: 417–37.
Domené HM, Hwa V, Argente J, et al; International ALS Collaborative Group. Human acid-labile subunit deficiency: clinical, endocrine and metabolic consequences. Horm Res 2009, 72: 129–41. Erratum in: Horm Res 2010, 73: 80.
Guha N, Dashwood A, Thomas NJ, Skingle AJ, Sönksen PH, Holt RI. IGF-I abuse in sport. Curr Drug Abuse Rev 2009, 2: 263–72.
Zhou R, Diehl D, Hoeflich A, Lahm H, Wolf E. IGF-binding protein-4: biochemical characteristics and functional consequences. J Endocrinol 2003, 178: 177–93.
Durai R, Davies M, Yang W, et al. Biology of insulin-like growth factor binding protein-4 and its role in cancer. Int J Oncol 2006, 28: 1317–25.
Conover CA. Insulin-like growth factor-binding proteins and bone metabolism. Am J Physiol Endocrinol Metab 2008, 294: E10–4.
Yi HK, Hwang PH, Yang DH, Kang CW, Lee DY. Expression of the insulin-like growth factors (IGFs) and the IGF-binding proteins (IGFBPs) in human gastric cancer cells. Eur J Cancer 2001, 37: 2257–63.
Wright RJ, Holly JM, Galea R, Brincat M, Mason HD. Insulin-like growth factor (IGF)-independent effects of IGF binding protein-4 on human granulosa cell steroidogenesis. Biol Reprod 2002, 67: 776–81.
Tripathi G, Salih DA, Drozd AC, Cosgrove RA, Cobb LJ, Pell JM. IGF-independent effects of insulin-like growth factor binding protein-5 (Igfbp5) in vivo. FASEB J 2009, 23: 2616–26.
Twigg SM, Baxter RC. Insulin-like growth factor (IGF)-binding protein 5 forms an alternative ternary complex with IGFs and the acid-labile subunit. J Biol Chem 1998, 273: 6074–9.
Bach LA. IGFBP-6 five years on; not so ‘forgotten’? Growth Horm IGF Res 2005, 15: 185–92.
Frystyk J. Exercise and the growth hormone-insulin-like growth factor axis. Med Sci Sports Exerc 2010, 42: 58–66.
Janssen JA. Insulin-like growth factor I: pros and cons of a bioassay. Horm Res Paediatr 2011, 76(Suppl 1): 106–10.
Varewijck AJ, Lamberts SW, Uitterlinden P, Hofland LJ, Janssen JA. IGF-I bioactivity better reflects growth hormone deficiency than total IGF-I. J Clin Endocrinol Metab 2011, 96: 2248–54.
Clemmons DR. Consensus statement on the standardization and evaluation of growth hormone and insulin-like growth factor assays. Clin Chem 2011, 57: 555–9.
Frystyk J, Freda P, Clemmons DR. The current status of IGF-I assays—a 2009 update. Growth Horm IGF Res 2010, 2: 8–18.
Frystyk J. Free insulin-like growth factors — measurements and relationships to growth hormone secretion and glucose homeostasis. Growth Horm IGF Res 2004, 14: 337–75.
Frystyk J, Ivarsen P, Støving RK, et al. Determination of free insulinlike growth factor-I in human serum: comparison of ultrafiltration and direct immunoradiometric assay. Growth Horm IGF Res 2001, 1: 117–27. Erratum in: Growth Horm IGF Res 2001, 1: 198–9.
Clemmons DR. IGF-I assays: current assay methodologies and their limitations. Pituitary 2007, 10: 121–8.
Antonelli G, Gatti R, Prearo M, De Palo EF. Salivary free insulinlike growth factor-I levels: effects of an acute physical exercise in athletes. J Endocrinol Invest 2009, 3: 1–5.
Renehan AG, Jones J, O’Dwyer ST, Shalet SM. Determination of IGF-I, IGF-II, IGFBP-2, and IGFBP-3 levels in serum and plasma: comparisons using the Bland-Altman method. Growth Horm IGF Res 2003, 1: 341–6.
Hauffa BP, Lehmann N, Bettendorf M, et al; German KIGS Board/Medical Outcome Study Group. Central laboratory reassessment of IGF-I, IGF-binding protein-3, and GH serum concentrations measured at local treatment centers in growth-impaired children: implications for the agreement between outpatient screening and the results of somatotropic axis functional testing. Eur J Endocrinol 2007, 15: 597–603.
Khosravi J, Diamandi A, Mistry J, Krischna RG. The high molecular weight insulin-like growth factor-binding protein complex: epitope mapping, immunoassay, and preliminary clinical evaluation. J Clin Endocrinol Metab 1999, 84: 2826–33.
Lassarre C, Binoux M. Measurement of intact insulin-like growth factor-binding protein-3 in human plasma using a ligand immunofunctional assay. J Clin Endocrinol Metab 2001, 86: 1260–6.
Langkamp M, Weber K, Kirschner M, Pridzun L, Ranke MB. Validation of functional insulin-like growth factor binding protein-3 measurement by a ligand immunoassay. Clin Lab 2010, 5: 535–42.
Harris TG, Strickler HD, Yu H, et al. Specimen processing time and measurement of total insulin-like growth factor-I (IGF-I), free IGF-I, and IGF binding protein-3 (IGFBP-3). Growth Horm IGF Res 2006, 1: 86–92.
Hartog H, van der Graaf WT, Wesseling J, van der Veer E, Boezen HM. Measurement of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 after delayed separation of whole blood samples. Clin Biochem 2008, 41: 636–9.
Abellan R, Ventura R, Palmi I, et al. Immunoassays for the measurement of IGF-II, IGFBP-2 and -3, and ICTP as indirect biomarkers of recombinant human growth hormone misuse in sport. Values in selected population of athletes. J Pharm Biomed Anal 2008, 48: 844–52.
Nguyen TV, Nelson AE, Howe CJ, et al. Within-subject variability and analytic imprecision of insulinlike growth factor axis and collagen markers: implications for clinical diagnosis and doping tests. Clin Chem 2008, 5: 1268–76.
Nindl BC, Pierce J. Insulin-like growth factor I as a biomarker of health, fitness, and training status. Med Sci Sports Exerc 2010, 42: 39–49.
Burgers AM, Biermasz NR, Schoones JW, et al. Meta-analysis and dose-response metaregression: circulating insulin-like growth factor I (IGF-I) and mortality. J Clin Endocrinol Metab 2011, 96: 2912–20.
Nindl BC, Alemany JA, Tuckow AP, Kellogg MD, Sharp MA, Patton JF. Effects of exercise mode and duration on 24-h IGF-I system recovery responses. Med Sci Sports Exerc 2009, 41: 1261–70.
Bang P, Brandt J, Degerblad M, et al. Exercise-induced changes in insulin-like growth factors and their low molecular weight binding protein in healthy subjects and patients with growth hormone deficiency. Eur J Clin Invest 1990, 20: 285–92.
Berg U, Bang P. Exercise and circulating insulin-like growth factor I. Horm Res 2004, 62(Suppl 1): 50–8.
Kraemer WJ, Marchitelli L, Gordon SE, et al. Hormonal and growth factor responses to heavy resistance exercise protocols. J Appl Physiol 1990, 69: 1442–50.
Nindl BC, Kraemer WJ, Marx JO, et al. Overnight responses of the circulating IGF-I system after acute, heavy-resistance exercise. J Appl Physiol 2001, 90: 1319–26.
Kraemer WJ, Aguilera BA, Terada M, et al. Responses of IGF-I to endogenous increases in growth hormone after heavy-resistance exercise. J Appl Physiol 1995, 79: 1310–5.
Kanaley JA, Frystyk J, Moller N, et al. The effect of submaximal exercise on immuno- and bioassayable IGF-I activity in patients with GH-deficiency and healthy subjects. Growth Horm IGF Res 2005, 15: 283–90.
Pilz-Burstein R, Ashkenazi Y, Yaakobovitz Y, et al. Hormonal response to Taekwondo fighting simulation in elite adolescent athletes. Eur J Appl Physiol 2010, 110: 1283–90.
De Palo EF, Antonelli G, Gatti R, Chiappin S, Spinella P, Cappellin E. Effects of two different types of exercise on GH/IGF axis in athletes. Is the free/total IGF-I ratio a new investigative approach?. Clin Chim Acta 2008, 387: 71–4.
Bermon S, Ferrari P, Bernard P, Altare S, Dolisi C. Responses of total and free insulin-like growth factor-I and insulin-like growth factor binding protein-3 after resistance exercise and training in elderly subjects. Acta Physiol Scand 1999, 165: 51–6.
Dall R, Lange KH, Kjaer M, et al. No evidence of insulin-like growth factor-binding protein 3 proteolysis during a maximal exercise test in elite athletes. J Clin Endocrinol Metab 2001, 86: 669–74.
Stokes K, Nevill M, Frystyk J, Lakomy H, Hall G. Human growth hormone responses to repeated bouts of sprint exercise with different recovery periods between bouts. J Appl Physiol 2005, 99: 1254–61.
Matheny RW, Merritt E, Zannikos SV, Farrar RP, Adamo ML. Serum IGF-I-deficiency does not prevent compensatory skeletal muscle hypertrophy in resistance exercise. Exp Biol Med (Maywood) 2009, 234: 164–70.
Berg U, Gustafsson T, Sundberg CJ, Kaijser L, Carlsson-Skwirut C, Bang P. Interstitial IGF-I in exercising skeletal muscle in women. Eur J Endocrinol 2007, 15: 427–35.
Frystyk J. Utility of free IGF-I measurements. Pituitary 2007, 1: 181–7.
Nguyen UN, Mougin F, Simon-Rigaud M.L, Rouillon JD, Marguet P, Regnard J. Influence of exercise duration on serum insulin-like growth factor and its binding proteins in athletes. Eur J Appl Physiol Occup Physiol 1998, 78: 533–7.
Copeland JL, Heggie L. IGF-I and IGFBP-3 during continuous and interval exercise. Int J Sports Med 2008, 29: 182–7.
Turgut G, Kaptanoglu B, Turgut S, Genç O, Tekintürk S. Influence of acute exercise on urinary protein, creatinine, insulin-like growth factor-I (IGF-I) and IGF binding protein-3 concentrations in children. Tohoku J Ex Med 2003, 201: 165–70.
Arikawa AY, Kurzer MS, Thomas W, Schmitz KH. No effect of exercise on insulin-like growth factor-I, insulin, and glucose in young women participating in a 16-week randomized controlled trial. Cancer Epidemiol Biomarkers Prev 2010, 19: 2987–90.
Borst SE, De Hoyos DV, Garzarella L, et al. Effects of resistance training on insulin-like growth factor-I and IGF binding proteins. Med Sci Sports Exerc 2001, 33: 648–53.
Manetta J, Brun JF, Fedou C, Maïmoun L, Prefaut C, Mercier J. Serum levels of insulin-like growth factor-I (IGF-I), and IGF-binding proteins-1 and -3 in middle-aged and young athletes versus sedentary men: relationship with glucose disposal. Metabolism 2003, 52: 821–6.
Manetta J, Brun JF, Maïmoun L, Fédou C, Préfaut C, Mercier J. The effects of intensive training on insulin-like growth factor I (IGF-I) and IGF binding proteins 1 and 3 in competitive cyclists: relationships with glucose disposal. J Sports Sci 2003, 21: 147–54.
Elloumi M, El Elj N, Zaouali M, et al. IGFBP-3, a sensitive marker of physical training and overtraining. Br J Sports Med 2005, 39: 604–10.
Izquierdo M, Ibañez J, González-Badillo JJ, et al. Differential effects of strength training leading to failure versus not to failure on hormonal responses, strength, and muscle power gains. J Appl Physiol 2006, 100: 1647–56.
Berg U, Enqvist JK, Mattsson CM, et al. Lack of sex differences in the IGF-IGFBP response to ultra endurance exercise. Scand J Med Sci Sports 2008, 18: 706–14.
Nishida Y, Matsubara T, Tobina T, et al. Effect of low-intensity aerobic exercise on insulin-like growth factor-I and insulin-like growth factor-binding proteins in healthy men. Int J Endocrinol 2010, 2010 pii: 452820.
Rarick KR, Pikosky MA, Grediagin A, et al. Energy flux, more so than energy balance, protein intake, or fitness level, influences insulin-like growth factor-I system responses during 7 days of increased physical activity. J Appl Physiol 2007, 103: 1613–21.
Eliakim A, Scheett TP, Newcomb R, Mohan S, Cooper DM. Fitness, training, and the growth hormone—>insulin-like growth factor I axis in prepubertal girls. J Clin Endocrinol Metab 2001, 86: 2797–802.
Nindl BC, Headley SA, Tuckow AP, et al. IGF-I system responses during 12 weeks of resistance training in end-stage renal disease patients. Growth Horm IGF Res 2004, 14: 245–50.
Eliakim A, Brasel JA, Mohan S, Wong WL, Cooper DM. Increased physical activity and the growth hormone-IGF-I axis in adolescent males. Am J Physiol 1998, 275: R308–14.
Poehlman ET, Copeland KC. Influence of physical activity on insulin-like growth factor-I in healthy younger and older men. J Clin Endocrinol Metab 1990, 71: 1468–73.
Nemet D, Connolly PH, Pontello-Pescatello AM, et al. Negative energy balance plays a major role in the IGF-I response to exercise training. J Appl Physiol 2004, 96: 276–82.
de Sousa MV, Madsen K, Simões HG, et al. Effects of carbohydrate supplementation on competitive runners undergoing overload training followed by a session of intermittent exercise. Eur J Appl Physiol 2010, 109: 507–16.
Alemany JA, Nindl BC, Kellogg MD, Tharion WJ, Young AJ, Montain SJ. Effects of dietary protein content on IGF-I, testosterone, and body composition during 8 days of severe energy deficit and arduous physical activity. J Appl Physiol 2008, 105: 58–64.
Fair AM, Montgomery K. Energy balance, physical activity, and cancer risk. Methods Mol Biol 2009, 472: 57–88.
Ben Ounis O, Elloumi M, Zouhal H, et al. Effect of individualized exercise training combined with diet restriction on inflammatory markers and IGF-1/IGFBP-3 in obese children. Ann Nutr Metab 2010, 56: 260–6.
Nindl BC, Alemany JA, Tuckow AP, et al. Circulating bioactive and immunoreactive IGF-I remain stable in women, despite physical fitness improvements after 8 weeks of resistance, aerobic, and combined exercise training. J Appl Physiol 2010, 109: 112–20.
Hameed M, Toft AD, Pedersen BK, Harridge SD, Goldspink G. Effects of eccentric cycling exercise on IGF-I splice variant expression in the muscles of young and elderly people. Scand J Med Sci Sports 2008, 18: 447–52.
Hameed M, Orrell RW, Cobbold M, Goldspink G, Harridge SD. Expression of IGF-I splice variants in young and old human skeletal muscle after high resistance exercise. J Physiol 2003, 547: 247–54.
Heinemeier KM, Olesen JL, Schjerling P, et al. Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types. J Appl Physiol 2007, 102: 573–81.
Bamman MM, Shipp JR, Jiang J, et al. Mechanical load increases muscle IGF-I and androgen receptor mRNA concentrations in humans. Am J Physiol Endocrinol Metab 2001, 280: E383–90.
Goldspink G. Age-related muscle loss and progressive dysfunction in mechanosensitive growth factor signalling. Ann N Y Acad Sci 2004, 1019: 294–8.
Velloso CP, Harridge SD. Insulin-like growth factor-I E peptides: implications for aging skeletal muscle. Scand J Med Sci Sports 2010, 20: 20–7.
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Gatti, R., De Palo, E.F., Antonelli, G. et al. IGF-I/IGFBP system: Metabolism outline and physical exercise. J Endocrinol Invest 35, 699–707 (2012). https://doi.org/10.3275/8456
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DOI: https://doi.org/10.3275/8456