Novel markers to detect recombinant human insulin‐like growth factor‐I (rhIGF‐I)/rhIGF binding protein‐3 (rhIGFBP‐3) misuse in athletes

Abstract

Insulin-like growth factor-I (IGF-I) is abused by elite athletes for its metabolic and anabolic effects. We have previously shown that it is possible to detect IGF-I misuse by measuring serum IGF-I and procollagen type III amino-terminal propeptide (P-III-NP) but a pilot study suggested measuring IGF-II, IGF binding protein-2 (IGFBP-2) and acid-labile subunit (ALS) may improve the detection of IGF-I administration. The aim of the study was to assess this in a randomized controlled trial. Twenty-six female and 30 male recreational athletes were randomized to 28 days' treatment with placebo or recombinant human (rh)IGF-I/rhIGF binding protein-3 (IGFBP-3) complex (30 mg/day or 60 mg/day), followed by 56 days' washout. IGF-II, IGFBP-2 and ALS (women only) were measured using commercial immunoassays. IGFBP-2 increased and IGF-II decreased in response to both low and high dose rhIGF-I/rhIGFBP-3 in both women and men while ALS decreased in women in response to high dose rhIGF-I/rhIGFBP-3. Two days after discontinuing treatment, significant differences remained between the three treatment groups in IGFBP-2 and IGF-II, but not ALS. Thereafter there were no significant differences between the three treatment groups in any of the markers. Combining IGF-I with IGF-II and/or IGFBP-2 improved the performance of the test to detect rhIGF-I/rhIGFBP-3 administration in both women and men. Copyright © 2016 John Wiley & Sons, Ltd.

Potential Role of Insulin-Like Growth Factors in Myofascial Pain Syndrome

“…Similar to the lower levels of circulating IGF-1 associated with older age, 101 these findings suggest that local IGF-1 levels in muscle may also play a role in muscle regeneration in elderly people. Nevertheless, in older muscle, mechanical overloading increased the level of IGF-1 to a lesser degree than in younger muscle 98,132 . Investigations are warranted to ascertain whether levels of muscle IGF-1 mediate the relationship between reduced age-related muscle wasting and resistance exercise and GH administration.…”

“…Because of its metabolic and anabolic effects, IGF-1 is often abused by elite athletes as a performance-enhancing agent 33,98 . Non–IGF-1–abusing athletes tend to have higher blood levels of IGF-1 than the general population.…”

“…• IGF-1 levels are higher in athletes than in the general population. 33,98 • Aerobic exercise increases circulating IGF-2. IGF in the aging muscle • IGF-1 levels decline with aging.…”

“…Nevertheless, in older muscle, mechanical overloading increased the level of IGF-1 to a lesser degree than in younger muscle. 98,132 Investigations are warranted to ascertain whether levels of muscle IGF-1 mediate the relationship between reduced age-related muscle wasting and resistance exercise and GH administration.…”

Coupling Complete Blood Count and Steroidomics to Track Low Doses Administration of Recombinant Growth Hormone: An Anti-Doping Perspective

“…A possible strategy to improve the accuracy of such biomarkers-related test is to increase the number of biomarkers involved. In this sense, further peptide markers linked to GH's cascade pathway have already been proposed by some authors (Holt et al, 2015(Holt et al, , 2017Sieckmann et al, 2020). The extension of the list of biomarkers of GH has already been approached by omics strategies, like proteomics (Ding et al, 2008(Ding et al, , 2011Duran-Ortiz et al, 2017) and metabolomics (Narduzzi et al, 2019;2020b).…”