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

Nindl, Bradley C.; Urso, Maria L.; Pierce, Joseph R.; Scofield, Dennis E.; Barnes, Brian R.; Kraemer, William J.; Anderson, Jeffrey M.; Maresh, Carl M.; Beasley, Kathleen N.; Zambraski, Edward J.

doi:10.1152/ajpregu.00275.2012

Cited by 21 publications

(23 citation statements)

References 39 publications

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“…There is no evidence, however, that the hepatic-derived IGF-1, mediated through release via the GH-IGF-1 axis, and measured in circulation is related to levels in the muscle. In fact, a recent study by Nindl and colleagues showed that there was no relationship between IGF-1 measured in the blood and IGF-1 protein content within the muscle [41]. The lack of correlation between muscle hypertrophy and IGF-1 measured in the blood observed in this study is not surprising in light of the work by Nindl et al showing no relationship between IGF-1 protein in the muscle or interstitial space and IGF-1 in the blood [41].…”

Section: Discussionmentioning

confidence: 99%

Muscular and Systemic Correlates of Resistance Training-Induced Muscle Hypertrophy

et al. 2013

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PurposeTo determine relationships between post-exercise changes in systemic [testosterone, growth hormone (GH), insulin like grow factor 1 (IGF-1) and interleukin 6 (IL-6)], or intramuscular [skeletal muscle androgen receptor (AR) protein content and p70S6K phosphorylation status] factors in a moderately-sized cohort of young men exhibiting divergent resistance training-mediated muscle hypertrophy.MethodsTwenty three adult males completed 4 sessions•wk-1 of resistance training for 16 wk. Muscle biopsies were obtained before and after the training period and acutely 1 and 5 h after the first training session. Serum hormones and cytokines were measured immediately, 15, 30 and 60 minutes following the first and last training sessions of the study.ResultsMean fiber area increased by 20% (range: -7 to 80%; P<0.001). Protein content of the AR was unchanged with training (fold change = 1.17 ± 0.61; P=0.19); however, there was a significant correlation between the changes in AR content and fiber area (r=0.60, P=0.023). Phosphorylation of p70S6K was elevated 5 hours following exercise, which was correlated with gains in mean fiber area (r=0.54, P=0.007). There was no relationship between the magnitude of the pre- or post-training exercise-induced changes in free testosterone, GH, or IGF-1 concentration and muscle fiber hypertrophy; however, the magnitude of the post exercise IL-6 response was correlated with muscle hypertrophy (r=0.48, P=0.019).ConclusionPost-exercise increases in circulating hormones are not related to hypertrophy following training. Exercise-induced changes in IL-6 correlated with hypertrophy, but the mechanism for the role of IL-6 in hypertrophy is not known. Acute increases, in p70S6K phosphorylation and changes in muscle AR protein content correlated with muscle hypertrophy implicating intramuscular rather than systemic processes in mediating hypertrophy.

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Section: Discussionmentioning

confidence: 99%

Muscular and Systemic Correlates of Resistance Training-Induced Muscle Hypertrophy

et al. 2013

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“…Of the two, IGF-I has been most extensively studied and is secreted as it is produced by the liver in response to GH stimulation. Only 2% of IGF-I circulates in its free form; most circulates as a binary (20-25%) or ternary complex (∼75%) (146)(147)(148)(149). In its binary form, IGF-I circulates with one of seven binding proteins whereas in its ternary form, IGF-I circulates with IGFBP-3 and its acid labile subunit (ALS).…”

Section: Current Perspectives On Igf-i and Physiological Adaptations mentioning

confidence: 99%

“…Exercise duration and total work also may impact IGFBP-1 changes but it was not see that the modality had as much impact on the response patterns. With the novel technique of microdialysis to measure IGF-I in the interstitial fluid, Nindl et al (149) showed total and free IGF-I and IGFBP-3 were elevated. However, IGF-I in interstitial fluid was unaltered following high-power resistance type exercise.…”

Section: Acute Responses and Chronic Adaptations Of Igfs To Resistancmentioning

confidence: 99%

Growth Hormone(s), Testosterone, Insulin-Like Growth Factors, and Cortisol: Roles and Integration for Cellular Development and Growth With Exercise

et al. 2020

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Hormones are largely responsible for the integrated communication of several physiological systems responsible for modulating cellular growth and development. Although the specific hormonal influence must be considered within the context of the entire endocrine system and its relationship with other physiological systems, three key hormones are considered the "anabolic giants" in cellular growth and repair: testosterone, the growth hormone superfamily, and the insulin-like growth factor (IGF) superfamily. In addition to these anabolic hormones, glucocorticoids, mainly cortisol must also be considered because of their profound opposing influence on human skeletal muscle anabolism in many instances. This review presents emerging research on: (1) Testosterone signaling pathways, responses, and adaptations to resistance training; (2) Growth hormone: presents new complexity with exercise stress; (3) Current perspectives on IGF-I and physiological adaptations and complexity these hormones as related to training; and (4) Glucocorticoid roles in integrated communication for anabolic/catabolic signaling. Specifically, the review describes (1) Testosterone as the primary anabolic hormone, with an anabolic influence largely dictated primarily by genomic and possible non-genomic signaling, satellite cell activation, interaction with other anabolic signaling pathways, upregulation or downregulation of the androgen receptor, and potential roles in co-activators and transcriptional activity; (2) Differential influences of growth hormones depending on the "type" of the hormone being assayed and the magnitude of the physiological stress; (3) The exquisite regulation of IGF-1 by a family of binding proteins (IGFBPs 1-6), which can either stimulate or inhibit biological action depending on binding; and (4) Circadian patterning and newly discovered variants of glucocorticoid isoforms largely dictating glucocorticoid sensitivity and catabolic, muscle sparing, or pathological influence. The downstream integrated anabolic and catabolic mechanisms of these hormones not only affect the ability of skeletal muscle to generate force; they also have Kraemer et al. Anabolic and Catabolic Hormones and Exercise implications for pharmaceutical treatments, aging, and prevalent chronic conditions such as metabolic syndrome, insulin resistance, and hypertension. Thus, advances in our understanding of hormones that impact anabolic: catabolic processes have relevance for athletes and the general population, alike.

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“…) do not alter systemic IGF‐1), and does not reflect local IGF‐1 signalling after exercise (Nindl et al . ). Further, the activity and half‐life of systemic IGF‐1 is heavily influenced by IGF binding proteins and an acid‐labile subunit (Jones & Clemmons, ).…”

Section: Introductionmentioning

confidence: 97%

“…By contrast, exercise-induced changes in circulating IGF-1 are equivocal, with increases, decreases and no changes reported (Kraemer et al 1990(Kraemer et al , 1991(Kraemer et al , 1995. Systemic IGF-1, which is stimulated by pituitary-released GH and is primarily the result of liver secretions (IGF-1Ea isoform), is distinct from local compartments of IGF-1 (overexpression of muscle IGF-1 ( Barton-Davis et al 1998) and tendon injection of GH (Vestergaard et al 2012) do not alter systemic IGF-1), and does not reflect local IGF-1 signalling after exercise (Nindl et al 2012). Further, the activity and half-life of systemic IGF-1 is heavily influenced by IGF binding proteins and an acid-labile subunit (Jones & Clemmons, 1995).…”

Section: Introductionmentioning

confidence: 99%

The exercise‐induced biochemical milieu enhances collagen content and tensile strength of engineered ligaments

West

Lee-Barthel

McIntyre

et al. 2015

The Journal of Physiology

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Key pointsr Exercise acutely increases the concentrations of metabolites and hormones such as growth hormone (GH) and, to a lesser extent, insulin-like growth factor 1 (IGF-1); however, the biological function of this response is unclear.r Pharmacological administration of these hormones stimulates collagen synthesis in muscle and tendon; however, whether the post-exercise biochemical milieu has a similar action is unknown.r Treating engineered ligaments with serum obtained from young healthy men after exercise resulted in more collagen and improved tensile strength over those treated with serum from resting men.r Further, we show that the increase in collagen induced by post-exercise serum (i) is not reproduced by treatment with recombinant GH or IGF-1, and (ii) is associated with the activation of PI3 kinase/mTORC1 and ERK1/2 signalling.Abstract Exercise stimulates a dramatic change in the concentration of circulating hormones, such as growth hormone (GH), but the biological functions of this response are unclear. Pharmacological GH administration stimulates collagen synthesis; however, whether the post-exercise systemic milieu has a similar action is unknown. We aimed to determine whether the collagen content and tensile strength of tissue-engineered ligaments is enhanced by serum obtained post-exercise. Primary cells from a human anterior cruciate ligament (ACL) were used to engineer ligament constructs in vitro. Blood obtained from 12 healthy young men 15 min after resistance exercise contained GH concentrations that were ß7-fold greater than resting serum (P < 0.001), whereas IGF-1 was not elevated at this time point (P = 0.21 vs. rest). Ligament constructs were treated for 7 days with medium supplemented with serum obtained at rest (RestTx) or 15 min post-exercise (ExTx), before tensile testing and collagen content analysis. Compared with RestTx, ExTx enhanced collagen content (+19%; 181 ± 33 vs. 215 ± 40 μg per construct P = 0.001) and ligament mechanical properties -maximal tensile load (+17%, P = 0.03 vs. RestTx) and ultimate tensile strength (+10%, P = 0.15 vs. RestTx). In a separate set of engineered ligaments, recombinant IGF-1, but not GH, enhanced collagen content and mechanics. Bioassays in 2D culture revealed that acute treatment with post-exercise serum activated mTORC1 and ERK1/2. In conclusion, the post-exercise biochemical milieu, but not recombinant GH, enhances collagen content and tensile strength of engineered ligaments, in association with mTORC1 and ERK1/2 activation.

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

Cited by 21 publications

References 39 publications

Muscular and Systemic Correlates of Resistance Training-Induced Muscle Hypertrophy

Muscular and Systemic Correlates of Resistance Training-Induced Muscle Hypertrophy

Growth Hormone(s), Testosterone, Insulin-Like Growth Factors, and Cortisol: Roles and Integration for Cellular Development and Growth With Exercise

The exercise‐induced biochemical milieu enhances collagen content and tensile strength of engineered ligaments

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