IGF-I measurement across blood, interstitial fluid, and muscle biocompartments following explosive, high-power exercise

2012 ◽  
Vol 303 (10) ◽  
pp. R1080-R1089 ◽  
Author(s):  
Bradley C. Nindl ◽  
Maria L. Urso ◽  
Joseph R. Pierce ◽  
Dennis E. Scofield ◽  
Brian R. Barnes ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Vastus Lateralis ◽  
Repetition Maximum ◽  
Time Points ◽  
Factor I ◽  
Plyometric Exercise ◽  
Igf I ◽  
Mrna Content ◽  
Exercise Induced ◽  
Induced Changes

Insulin-like growth factor-I (IGF-I) resides across different biocompartments [blood, interstitial fluid (ISF), and muscle]. Whether circulating IGF-I responses to exercise reflect local events remains uncertain. We measured the IGF-I response to plyometric exercise across blood, ISF, and muscle biopsy from the vastus lateralis. Twenty volunteers (8 men, 12 women, 22 ± 1 yr) performed 10 sets of 10 plyometric jump repetitions at a 40% 1-repetition maximum. Blood, ISF, and muscle samples were taken pre- and postexercise. Circulating IGF-I increased postexercise: total IGF-I (preexercise = 546 ± 42, midexercise = 585 ± 43, postexercise = 597 ± 45, +30 = 557 ± 42, +60 = 536 ± 40, +120 = 567 ± 42 ng/ml; midexercise, postexercise, and +120 greater than preexercise, P < 0.05); Free IGF-I (preexercise = 0.83 ± 0.09, midexercise = 0.78 ± 0.10, postexercise = 0.79 ± 0.11, +30 = 0.93 ± 0.10, +60 = 0.88 ± 0.10, + 120 = 0.91 ± 0.11 ng/ml; +30 greater than all other preceding time points, P < 0.05). No exercise-induced changes were observed for ISF IGF-I (preexercise = 2.35 ± 0.29, postexercise = 2.46 ± 0.35 ng/ml). No changes were observed for skeletal muscle IGF-I protein, although IGF-I mRNA content increased ∼40% postexercise. The increase in circulating total and free IGF-I was not correlated with increases in ISF IGF-I or muscle IGF-I protein content. Our data indicate that exercise-induced increases in circulating IGF-I are not reflective of local IGF-I signaling.

A novel, noninvasive transdermal fluid sampling methodology: IGF-I measurement following exercise

2011 ◽  
Vol 300 (6) ◽  
pp. R1326-R1332 ◽  
Author(s):  
D. E. Scofield ◽  
H. L. McClung ◽  
J. P. McClung ◽  
W. J. Kraemer ◽  
K. R. Rarick ◽  
...  
Keyword(s):  
Acute Exercise ◽  
Active Muscle ◽  
Acute Bout ◽  
Factor I ◽  
Exercise Condition ◽  
Plyometric Exercise ◽  
Igf I ◽  
Exercise Induced ◽  
Induced Changes ◽  
Fluid Sampling

This study tested the hypothesis that transdermal fluid (TDF) provides a more sensitive and accurate measure of exercise-induced increases in insulin-like growth factor-I (IGF-I) than serum, and that these increases are detectable proximal, but not distal, to the exercising muscle. A novel, noninvasive methodology was used to collect TDF, followed by sampling of total IGF-I (tIGF-I) and free IGF-I (fIGF-I) in TDF and serum following an acute bout of exercise. Experiment 1: eight men (23 ± 3 yrs, 79 ± 7 kg) underwent two conditions (resting and 60 min of cycling exercise at 60% V̇o2peak) in which serum and forearm TDF were collected for comparison. There were no significant changes in tIGF-I or fIGF-I in TDF obtained from the forearm or from serum following exercise ( P > 0.05); however, the proportion of fIGF-I to tIGF-I in TDF was approximately fourfold greater than that of serum ( P ≤ 0.05). These data suggest that changes in TDF IGF-I are not evident when TDF is sampled distal from the working tissue. To determine whether exercise-induced increases in local IGF-I could be detected when TDF was sampled directly over the active muscle group, we performed a second experiment. Experiment 2: fourteen subjects (22 ± 4 yr, 68 ± 11 kg) underwent an acute plyometric exercise condition consisting of 10 sets of 10 plyometric jumps with 2-min rest between sets. We observed a significant increase in TDF tIGF-I following exercise ( P ≤ 0.05) but no change in serum tIGF-I ( P > 0.05). Overall, these data suggest that TDF may provide a noninvasive means of monitoring acute exercise-induced changes in local IGF-I when sampled in proximity to exercising muscles. Moreover, our finding that the proportion of free to tIGF-I was greater in TDF than in serum suggests that changes in local IGF-I may be captured more readily using this system.

Tissue IGF-I protein and mRNA responses to a single injection of somatotropin

1995 ◽  
Vol 269 (4) ◽  
pp. E627-E635 ◽  
Author(s):  
T. G. Ramsay ◽  
I. B. Chung ◽  
S. M. Czerwinski ◽  
J. P. McMurtry ◽  
R. W. Rosebrough ◽  
...  
Keyword(s):  
Latissimus Dorsi ◽  
Single Injection ◽  
Vastus Lateralis ◽  
Mrna Levels ◽  
Lipogenic Enzyme ◽  
Adipose Tissues ◽  
Factor I ◽  
Porcine Somatotropin ◽  
Igf I ◽  
Selection For

Swine were divided into four groups of 11 animals at 40 kg body wt. Swine within a group were given a single porcine somatotropin (pST) injection (200 micrograms/kg) or buffer at 0800. Blood, liver (L), latissimus dorsi (LD), semitendinosus (STS), vastus lateralis (VL), dorsal subcutaneous (SQ), and perirenal (PR) adipose tissues were sampled at 0, 1, 2, 4, 8, 12, 16, and 24 h postinjection. Blood urea nitrogen was depressed by 16 h. Insulin was elevated by approximately 350% at 8 h. Lipogenic enzyme activities in adipose tissues were not affected by pST treatment. Insulin-like growth factor I (IGF-I) mRNA levels increased rapidly in SQ, PR, and L to a single pST administration, whereas they increased only slightly in VL. IGF-I mRNA concentrations in LD and STS were unaffected by pST treatment. IGF-I protein content of tissues changed little during the first 24 h postinjection. These data suggest that individual tissues differ in timing and degree of response to pST. Conflicting results reported after pST treatment could, in part, be due to tissue selection for sampling or sample timing.

GH elevates serum IGF-I levels but does not alter mucosal atrophy in parenterally fed rats

1997 ◽  
Vol 272 (5) ◽  
pp. G1100-G1108 ◽  
Author(s):  
C. A. Peterson ◽  
H. V. Carey ◽  
P. L. Hinton ◽  
H. C. Lo ◽  
D. M. Ney
Keyword(s):  
Specific Activity ◽  
Growth Parameters ◽  
Villus Height ◽  
Intestinal Growth ◽  
Factor I ◽  
Ion Secretion ◽  
Igf I ◽  
Mucosal Mass ◽  
And Function ◽  
Induced Changes

Growth hormone (GH) action is primarily mediated by insulin-like growth factor I (IGF-I), although both growth factors show tissue-selective effects. We investigated the effects of GH, IGF-I, and GH plus IGF-I on jejunal growth and function in rats maintained with total parenteral nutrition (TPN) and given recombinant human GH (rhGH) (400 micrograms/day sc, twice daily) and/or rhIGF-I (800 micrograms/day in TPN solution) for 5 days. Administration of GH or IGF-I alone produced similar increases in serum IGF-I levels and body weight; GH plus IGF-I further increased these parameters. TPN reduced mucosal mass, protein and DNA content, villus height, crypt depth, and enterocyte migration rate. IGF-I or GH plus IGF-I produced equivalent increases in all intestinal growth parameters; GH alone had no effect. GH, IGF-I, or GH plus IGF-I reduced TPN-induced increases in sucrase-specific activity. IGF-I, but not GH, attenuated TPN-induced increases in tissue conductance and carbachol-stimulated ion secretion. In contrast to IGF-I, GH does not stimulate intestinal growth during TPN and has less effect on normalizing TPN-induced changes in epithelial function.

IGF-I Measurement Across Blood, Interstitial Fluid and Muscle Biocompartments: Exercise-Induced Akt Phosphorylation Does Not Involve The IGF-I System

2010 ◽  
Vol 42 ◽  
pp. 51-52
Author(s):  
Bradley C. Nindl ◽  
Maria L. Urso ◽  
Joseph R. Pierce ◽  
Brian R. Barnes ◽  
William J. Kraemer ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Akt Phosphorylation ◽  
Igf I ◽  
Exercise Induced

The involvement of insulin-like growth factor-I in local control of steroidogenesis and DNA synthesis of Leydig and non-Leydig cells in the rat testicular interstitium

1993 ◽  
Vol 138 (1) ◽  
pp. 107-114 ◽  
Author(s):  
A. Moore ◽  
I. D. Morris
Keyword(s):  
Growth Factor ◽  
Dna Synthesis ◽  
Leydig Cell ◽  
Interstitial Fluid ◽  
Binding Proteins ◽  
Interstitial Cells ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I

ABSTRACT Insulin-like growth factor-I (IGF-I) peptide, receptors and binding proteins are present in the rodent testis, which strongly implies that IGF-I has one or more testicular functions. In the present study we provide further information to support the concept that IGF-I is an important local mediator in the testis. High concentrations of IGF-I were measurable in interstitial fluid by radioimmunoassay, and IGF-I-binding proteins (IGFBPs) were readily detectable in interstitial fluid by ligand blotting, the predominant type being IGFBP-2. In vitro, IGF-I bound to testicular interstitial cells which did not have 3β-hydroxysteroid dehydrogenase (3β-HSD) activity and which were resistant to ethane dimethanesulphonate treatment. In vitro, IGF-I receptor-mediated actions increased both steroidogenesis and DNA synthesis. Insulin stimulated DNA synthesis at concentrations appropriate to cross-react with the IGF-I receptor, and this effect was greater in a testicular interstitial Leydig cell-depleted cell population compared with a Leydig cell-enriched cell culture. Furthermore, combinations of epidermal growth factor or transforming growth factor -α together with insulin appeared to act synergistically, causing extremely large increases in [3 H]thymidine incorporation in the interstitial cells. These results support a paracrine and/or autocrine role for IGF-I in interstitial cell growth and development. Journal of Endocrinology (1993) 138, 107–114

scholarly journals Interpretation of exercise-induced changes in human skeletal muscle mRNA expression depends on the timing of the post-exercise biopsies

2020 ◽  
Author(s):  
Jujiao Kuang ◽  
Cian McGinley ◽  
Matthew J-C Lee ◽  
Nicholas J Saner ◽  
Andrew Garnham ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Mrna Expression ◽  
Molecular Response ◽  
Muscle Sample ◽  
Post Exercise ◽  
Time Points ◽  
Short Period ◽  
Mrna Content ◽  
Exercise Induced

ABSTRACTAimExercise elicits a range of adaptive responses in skeletal muscle that include changes in mRNA expression. To better understand the health benefits of exercise training, it is essential to investigate the underlying molecular mechanisms of skeletal muscle adaptations to exercise. However, most studies have assessed the molecular events at a few convenient time points within a short time frame post exercise, and the variations of gene expression kinetics have not been addressed systematically.MethodMuscle biopsies were collected from nine participants at baseline and six time points (0, 3, 9, 24, 48, and 72 h) following a session of high-intensity interval exercise. We assessed the mRNA content of 23 gene isoforms from the muscle samples.ResultThe temporal patterns of target gene expression were highly variable and the mRNA contents detected were largely dependent on the muscle sample timing. The maximal levels of mRNA content of all tested target genes were observed between 3 to 48 h post exercise.ConclusionOur findings highlight a critical gap in knowledge regarding the molecular response to exercise, where the use of a few time points within a short period after exercise has led to an incomplete understanding of the molecular responses to exercise. The timing of muscle sampling for individual studies needs to be carefully chosen based on existing literature and preliminary analysis of the molecular targets of interest. We propose that a comprehensive time-course analysis on the exercise-induced transcriptional response in humans will significantly benefit the field of exercise molecular biology.

Sign in / Sign up

Export Citation Format

Share Document