The Effects Of Acute And Chronic Exercise Training On IGFBP-3 Proteolysis
Bibliographic record
Abstract
Insulin-like growth factor binding protein-3 (IGFBP-3) is the primary binding protein for IGF-I and exists in both intact and fragmented (via proteolysis) forms. IGFBP-3 proteolysis is one mechanism whereby free IGF-I is liberated and made available to cellular receptors, however most studies have failed to demonstrate an exercise effect on IGFBP-3 proteolysis. PURPOSE: To test the hypothesis that both acute and chronic exercise can increase IGFBP-3 proteolysis. METHODS: A resistance training (RT) group (n = 10, 27±5 yr, 81±12 kg) and a generalized physical training group (PT) (n = 7, 29±5 yr, 85±10 kg) underwent 8 weeks of training (1.5 h/d, 5 d/wk). The RT group engaged in conventional weight lifting exercises, running/hiking and interval/agility drills, while the PT group engaged in callisthenic-type exercises and interval/agility running drills. An acute resistance exercise test (ARET) consisting of 6 sets of 10-RM squat was performed before and after training. Blood was sampled pre, mid-, post-, +15 min post-, and + 30 min post-ARET and analyzed for total and intact IGFBP-3. IGFBP-3 proteolysis was calculated as the relative difference between total and intact IGFBP-3. Serum albumin adjustments corrected for changes in plasma volume. Data were analyzed by using a repeated measures ANOVA and are presented as mean ± SE (P ≤ 0.05). RESULTS: For intact IGFBP-3, chronic training resulted in a significant 10 % increase (Pre: 892 ± 78; Post: 982 ± 111 ng/mL). Intact IGFBP-3 concentrations were also significantly increased by 8 % at the post-ARET time point (Pre: 907 ± 51; Mid: 947 ± 64; Post: 979 ± 68; +15min: 944 ± 62; +30min: 907 ± 49 ng/mL). IGFBP-3 proteolysis was significantly increased following chronic training (Pre: 22 ± 2; Post: 25 ± 3 %). IGFBP-3 proteolysis was significantly increased at the post-ARET time point (Pre: 23 ± 1; Mid: 24 ± 1; Post: 25 ± 2; +15min: 24 ± 1; +30min: 23 ± 1 %). CONCLUSIONS: We have demonstrated that IGFBP-3 proteolysis can be increased with both acute and chronic exercise. The increased IGFBP-3 proteolysis may be one exercise-associated mechanism that contributes to IGF-I mediated adaptations.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".