No evidence of insulin-like growth factor-binding protein 3 proteolysis during a maximal exercise test in elite athletes
Research output: Contribution to journal › Journal article › Research › peer-review
The aim of the present study was to examine the GH/insulin-like growth factor (IGF) axis, post exercise, with emphasis on IGF-binding protein (IGFBP)-3 proteolysis. Sixteen elite rowers (8 female/8 male) performed a stepwise submaximal rowing test followed by a 6- to 7-min-long maximal test. Blood samples were drawn at baseline, t = 0 (end of exercise) and t = 15, 30, 60, 90, and 120 min. GH and IGFBP-1 levels increased post exercise (P < 0.0005). Total IGF-I and IGF-II increased significantly post exercise (P < 0.0005) but not after albumin correction. Free IGF-I decreased after exercise with nadir coincidently with the IGFBP-1 peak, and free IGF-II decreased post exercise coincidently with the IGFBP-6 peak. IGFBP-3, measured by immunoradiometric assay, increased after exercise (P < 0.0005) but not after albumin adjustment. IGFBP-3 proteolysis (%) (measured by a specific in vitro proteolytic activity assay) and IGFBP-3 (measured by Western ligand blotting) were unchanged post exercise. Albumin-adjusted levels of IGFBP-6 increased by 18% (P < 0.0005), whereas IGFBP-2 and IGFBP-4 did not change significantly post exercise. Our findings do not support the hypothesis that short-term strenuous exercise induces major acute changes in the GH/IGF axis. To what degree the protein anabolic effects of regular exercise are associated with acute alterations in the GH/IGF axis remains unclear.
Original language | English |
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Journal | The Journal of clinical endocrinology and metabolism |
Volume | 86 |
Issue number | 2 |
Pages (from-to) | 669-74 |
Number of pages | 6 |
ISSN | 0021-972X |
DOIs | |
Publication status | Published - Feb 2001 |
- Adult, Analysis of Variance, Blotting, Western, Female, Human Growth Hormone/blood, Humans, Insulin-Like Growth Factor Binding Protein 1/blood, Insulin-Like Growth Factor Binding Protein 3/blood, Insulin-Like Growth Factor Binding Protein 6/blood, Insulin-Like Growth Factor Binding Proteins/blood, Insulin-Like Growth Factor I/analysis, Insulin-Like Growth Factor II/analysis, Male, Physical Exertion/physiology, Reproducibility of Results, Serum Albumin/analysis, Sex Characteristics, Sports/physiology, Time Factors
Research areas
ID: 193672889