Philip J Atherton

University of Nottingham, Nottigham, England, United Kingdom

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Publications (67)304.4 Total impact

  • AJP Endocrinology and Metabolism 05/2015; 308(9):E847. DOI:10.1152/ajpendo.00581.2014 · 4.09 Impact Factor
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    ABSTRACT: The anabolic effects of dietary protein on skeletal muscle depend on adequate skeletal muscle perfusion, which is impaired in older people. To explore fed-state muscle microvascular blood flow, protein metabolism and exercise-training status in older men. We measured leg blood flow (LBF), muscle microvascular blood volume (MBV) and muscle protein turnover under postabsorptive and fed-state (IV Glamin to double AA, dextrose to sustain glucose ∼7-7.5 mmol·l(-1) ) conditions in two groups: 10 untrained men (72.3 ± 1.4 y; BMI 26.5 ± 1.15 kg·m(2) ) and 10 men who had undertaken 20-weeks fully-supervised, whole-body resistance-exercise training (RET) (72.8 ± 1.4 y; BMI 26.3 ± 1.2 kg·m(2) ). We measured LBF by Doppler ultrasound and muscle MBV by contrast enhanced ultrasound (CEUS). Muscle protein synthesis (MPS) was measured using [1, 2-(13) C2 ] leucine with breakdown (MPB) and net protein balance (NPB) by ring-[D5 ] phenylalanine tracers. Plasma insulin was measured via ELISA and indices of anabolic signalling (e.g. Akt/mTORC1) by immunoblotting from muscle biopsies. Whereas older untrained men did not exhibit fed-state increases in LBF or MBV, the RET group exhibited increases in both LBF and MBV. Despite our hypothesis that enhanced fed-state circulatory responses would improve anabolic responses to nutrition, fed-sate increases in MPS (∼50-75%; P<0.001), were identical in both groups. Finally, whereas only the RET group exhibited fed-state suppression of MPB (∼-38%; P<0.05), positive net protein balance (NPB) achieved was similar in both groups. We conclude that RET enhances fed-state LBF and MBV and restores nutrient-dependent attenuation of MPB without robustly enhancing MPS or NPB. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    The Journal of Physiology 04/2015; DOI:10.1113/JP270343 · 4.54 Impact Factor
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    ABSTRACT: Dysregulated anabolic responses to nutrition/exercise may contribute to sarcopenia; however, these characteristics are poorly defined in female populations. We determined the effects of two-feeding regimes in older women (66±2.5y N=8/group): bolus-whey protein (WP-20 g) or novel low-dose leucine-enriched essential amino acids (EAA) (LEAA-3g [40% leucine]). Using (13)C6-Phenylalanine infusions, we quantified muscle (MPS) and albumin (APS) protein synthesis at baseline and both in response to feeding (FED) and feeding-plus-exercise (FED-EX; RE: 6×8 knee-extensions at 75%-1RM). We also quantified plasma insulin/AA concentrations, whole-leg (LBF)/muscle microvascular blood-flow (MBF), and muscle anabolic signaling by phospho-immunoblotting. Plasma insulinemia and EAA-aemia were markedly greater after WP than LEAA (P<0.001). Neither LEAA nor WP modified LBF in response to FED or FED-EX, while MBF increased to a similar extent in both groups, only after FED-EX (P<0.05). In response to FED, both WP and LEAA equally stimulated MPS 0-2h (P<0.05), abating thereafter (0-4h; P>0.05). In contrast, after FED-EX, MPS increased 0-2h and remained elevated 0-4h (P<0.05) with both WP and LEAA. No anabolic signals quantifiably increased after FED, but p70S6K1(Thr389) increased after FED-EX (2h; P<0.05). APS increased similarly after WP and LEAA. Older women remain subtly responsive to nutrition±exercise. Intriguingly though, bolus-WP offers no trophic advantage over LEAA. Copyright © 2015, American Journal of Physiology - Endocrinology and Metabolism.
    AJP Endocrinology and Metabolism 03/2015; DOI:10.1152/ajpendo.00481.2014 · 4.09 Impact Factor
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    Philip J. Atherton, Paul L. Greenhaff
    The Journal of Physiology 02/2015; 593(3). DOI:10.1113/jphysiol.2014.288373 · 4.54 Impact Factor
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    ABSTRACT: Background: The anabolic response of skeletal muscle to essential amino acids (EAAs) is dose dependent, maximal at modest doses, and short lived, even with continued EAA availability, a phenomenon termed “muscle-full.” However, the effect of EAA ingestion profile on muscle metabolism remains undefined. Objective: We determined the effect of Bolus vs. Spread EAA feeding in young men and hypothesized that muscle-full is regulated by a dose-, not delivery profile–, dependent mechanism. Methods: We provided 16 young healthy men with 15 g mixed-EAA, either as a single dose (“Bolus” n = 8) or in 4 fractions at 45-min intervals (“Spread” n = 8). Plasma insulin and EAA concentrations were assayed by ELISA and ion-exchange chromatography, respectively. Limb blood flow by was determined by Doppler ultrasound, muscle microvascular flow by Sonovue (Bracco) contrast-enhanced ultrasound, and phosphorylation of mammalian target of rapamycin complex 1 substrates by immunoblotting. Intermittent muscle biopsies were taken to quantify myofibrillar-bound 13C6-phenylalanine to determine muscle protein synthesis (MPS). Results: Bolus feeding achieved rapid insulinemia (13.6 μIU ⋅ mL−1, 25 min after commencement of feeding), aminoacidemia (∼2500 μM at 45 min), and capillary recruitment (+45% at 45 min), whereas Spread feeding achieved attenuated insulin responses, gradual low-amplitude aminoacidemia (peak: ∼1500 μM at 135 min), and no detectable capillary recruitment (all P < 0.01 vs. Bolus). Despite these differences, identical anabolic responses were observed; fasting fractional synthetic rates of 0.054% ⋅ h−1 (Bolus) and 0.066% ⋅ h−1 (Spread) increased to 0.095% and 0.104% ⋅ h−1 (no difference in increment or final values between regimens). With both Spread and Bolus feeding strategies, a latency of at least 90 min was observed before an upswing in MPS was evident. Similarly with both feeding strategies, MPS returned to fasting rates by 180 min despite elevated circulating EAAs. Conclusion: These data do not support EAA delivery profile as an important determinant of anabolism in young men at rest, nor rapid aminoacidemia/leucinemia as being a key factor in maximizing MPS. This trial was registered at clinicaltrials.gov as NCT01735539.
    Journal of Nutrition 01/2015; 145(2):jn. 114.199604. DOI:10.3945/jn.114.199604 · 4.23 Impact Factor
  • Equine Veterinary Journal 09/2014; 46:19-19. DOI:10.1111/evj.12323_43 · 2.37 Impact Factor
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    ABSTRACT: Aging is associated with a gradual loss of muscle mass termed sarcopenia, which has significant impact on quality-of-life. Because oxidative stress is proposed to negatively impact upon musculoskeletal aging, we investigated links between human aging and markers of oxidative stress, and relationships to muscle mass and strength in young and old nonsarcopenic and sarcopenic adults. Sixteen young and 16 old males (further subdivided into "old" and "old sarcopenic") were studied. The abundance of protein carbonyl adducts within skeletal muscle sarcoplasmic, myofibrillar, and mitochondrial protein subfractions from musculus vastus lateralis biopsies were determined using Oxyblot immunoblotting techniques. In addition, concentrations of recognized cytoprotective proteins (eg, heat shock proteins [HSP], αβ-crystallin) were also assayed. Aging was associated with increased mitochondrial (but not myofibrillar or sarcoplasmic) protein carbonyl adducts, independently of (stage-I) sarcopenia. Correlation analyses of all subjects revealed that mitochondrial protein carbonyl abundance negatively correlated with muscle strength ([1-repetition maximum], p = .02, r (2) = -.16), but not muscle mass (p = .13, r (2) = -.08). Abundance of cytoprotective proteins, including various HSPs (HSP 27 and 70), were unaffected by aging/sarcopenia. To conclude, these data reveal that mitochondrial protein carbonylation increases moderately with age, and that this increase may impact upon skeletal muscle function, but is not a hallmark of (stage-I) sarcopenia, per se.
    The Journals of Gerontology Series A Biological Sciences and Medical Sciences 03/2014; DOI:10.1093/gerona/glu007 · 4.98 Impact Factor
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    ABSTRACT: Muscle hypertrophy following resistance training (RT) involves activation of myofibrillar protein synthesis (MPS) to expand the myofibrillar protein pool. The degree of hypertrophy following RT is, however, highly variable and thus we sought to determine the relationship between the acute activation of MPS and RT-induced hypertrophy. We measured MPS and signalling protein activation after the first session of resistance exercise (RE) in untrained men (n = 23) and then examined the relation between MPS with magnetic resonance image determined hypertrophy. To measure MPS, young men (24±1 yr; body mass index = 26.4±0.9 kg•m(2)) underwent a primed constant infusion of L-[ring-(13)C6] phenylalanine to measure MPS at rest, and acutely following their first bout of RE prior to 16 wk of RT. Rates of MPS were increased 235±38% (P<0.001) above rest 60-180 min post-exercise and 184±28% (P = 0.037) 180-360 min post exercise. Quadriceps volume increased 7.9±1.6% (-1.9-24.7%) (P<0.001) after training. There was no correlation between changes in quadriceps muscle volume and acute rates of MPS measured over 1-3 h (r = 0.02), 3-6 h (r = 0.16) or the aggregate 1-6 h post-exercise period (r = 0.10). Hypertrophy after chronic RT was correlated (r = 0.42, P = 0.05) with phosphorylation of 4E-BP1(Thr37/46) at 1 hour post RE. We conclude that acute measures of MPS following an initial exposure to RE in novices are not correlated with muscle hypertrophy following chronic RT.
    PLoS ONE 02/2014; 9(2):e89431. DOI:10.1371/journal.pone.0089431 · 3.53 Impact Factor
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    ABSTRACT: We investigated architectural, functional, and molecular responses of human skeletal muscle to concentric (CON) or eccentric (ECC) resistance training (RT). Twelve young males performed 10 weeks of concentric (CON) or eccentric (ECC) resistance training (RT) (n = 6 CON, 6 ECC). An additional 14 males were recruited to evaluate acute muscle fascicle behaviour and molecular signalling in biopsies collected from vastus lateralis (VL) after 30 min of single bouts of CON or ECC exercise. VL volume was measured by magnetic resonance imaging. Muscle architecture (fascicle length, Lf; pennation angle, PA) was evaluated by ultrasonography. Muscle remodelling signals to CON or ECC loading (MAPK/AKT-mammalian target of rapamycin (mTOR) signalling) and inflammatory pathway (TNFα/Murf-1-MAFbx) were evaluated by immunoblotting. Despite the ~1.2 fold greater load of the ECC group, similar increases in muscle volume (+8% CON and +6% ECC) and in maximal voluntary isometric contraction (+9% CON and +11% ECC) were found after RT. However, increases in Lf were greater after ECC than CON (+12 vs. +5%) while increases in PA were greater in CON than ECC (+30 vs. +5%). Distinct architectural adaptations were associated with preferential growth in the distal regions of VL for ECC (+ECC +8% vs. +CON +2) and mid-belly for CON (ECC +7 vs. CON +11%). While MAPK activation (p38MAPK, ERK1/2, p90RSK) was specific to ECC, neither mode affected AKT-mTOR or inflammatory signalling 30 min after exercise. Muscle growth with CON and ECC RT occurs with different morphological adaptations reflecting distinct fibre fascicle behaviour and molecular responses. This article is protected by copyright. All rights reserved.
    Acta Physiologica 01/2014; DOI:10.1111/apha.12225 · 4.25 Impact Factor
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    ABSTRACT: Quantification of muscle protein synthesis (MPS) remains a cornerstone to understanding the control of muscle mass. Traditional (13)C-amino-acid tracer methodologies necessitate sustained bed-rest and intravenous cannulation(s), restricting studies to ~12h, and thus cannot holistically inform on diurnal MPS. This limits insight into the regulation of habitual muscle metabolism in health, ageing and disease while querying the utility of tracer-techniques to predict the long-term efficacy of anabolic/anti-catabolic interventions. We tested the efficacy of the D2O tracer for quantifying MPS over a period not feasible with (13)C tracers and too short to quantify changes in mass. Eight men (22±3.5y) undertook one-legged resistance-exercise over 8-d (4×8-10 repetitions: 80%-1RM every second-day, to yield 'non-exercised' vs. 'exercise' leg-comparisons) with Vastus Lateralis biopsies taken bi-laterally: 0, 2, 4 and 8-days. After day-0 biopsies, participants consumed a D2O bolus (150ml; 70-Atom%); saliva was collected daily. Fractional synthetic rates (FSR) of myofibrillar (MyoPS), sarcoplasmic (SPS) and collagen (CPS) protein-fractions were measured by GC-Pyrolysis-IRMS and TC/EA-IRMS. Body-water initially enriched at 0.16-0.24 APE, decayed at ~0.009%.d-1. In the non-exercised-leg, MyoPS was: 1.45±0.10%.d-1, 1.47±0.06%.d(-1), 1.35±0.07%.d-1 at 0-2, 0-4 and 0-8d respectively (~0.05-0.06%.h-1). MyoPS was greater in the exercised-leg (0-2d 1.97±0.13%.d(-1), 0-4d 1.96±0.15%.d-1; P<0.01, 0-8d 1.79±0.12%.d(-1); P<0.05). CPS was slower than MyoPS, but followed a similar pattern, with the exercised-leg tending to yield greater FSR's (0-2d; 1.14±0.13%.d-1 vs. 1.45±0.15%.d(-1), 0-4d; 1.13±0.07%.d(-1) vs. 1.47±0.18%.d(-1), 0-8d; 1.03±0.09%.d(-1) vs. 1.40±0.11%.d(-1)). SPS remained unchanged. Therefore, D2O has unrivaled utility to quantify day-to-day MPS in humans and inform on short-term changes in anabolism, and presumably, catabolism alike.
    AJP Endocrinology and Metabolism 12/2013; 306(5). DOI:10.1152/ajpendo.00650.2013 · 4.09 Impact Factor
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    ABSTRACT: Skeletal muscle anabolism associated with postprandial plasma aminoacidaemia and insulinaemia is contingent upon amino acids (AA) and insulin crossing the microcirculation-myocyte interface. In this study, we hypothesised that increasing muscle microvascular blood volume [flow] would enhance fed-state anabolic responses in muscle protein turnover. We studied 10 young men (23.2±2.1 y) under postabsorptive and fed (I.V Glamin® (~10 g AA), glucose ~7.5 mmol·l(-1))) conditions. Methacholine was infused into the femoral artery of one-leg to determine, via bilateral comparison, the effects of feeding alone versus feeding plus pharmacological vasodilation. We measured leg blood flow (LBF) [femoral artery] by Doppler-ultrasound, muscle microvascular blood volume (MBV) by contrast-enhanced ultrasound (CEUS), muscle protein synthesis (MPS) and breakdown (MPB; A-V balance modelling) and net protein balance (NPB) using [1,2-(13)C2] leucine and [D5] phenylalanine tracers via gas chromatography-mass spectrometry (GC-MS). Indices of anabolic-signalling/endothelial activation (e.g. Akt/mTORC1/NOS) were assessed using immunoblotting techniques. Under fed conditions, LBF (+12±5%, P<0.05), MBV (+25±10%, P<0.05) and MPS (+129±33%, P<0.05) increased. Infusion of methacholine further enhanced LBF (+126±12%, P<0.05) and MBV (+79±30%, P<0.05). In-spite of these radically different blood flow conditions, neither increases in MPS in response to feeding (0.04±0.004 vs. 0.08±0.01%·h(-1), P<0.05) nor improvements in NPB (-9.7±4.8 vs. 34.2±14.1 nmol·min(-1), P<0.05) were affected by methacholine infusion (MPS 0.07±0.01%·h(-1); NPB 50.6±15.5 nmol·min(-1)), whereas MPB was unaltered by either feeding or infusion of methacholine. Thus, enhancing LBF/MBV above that occurring naturally with feeding alone, does not improve muscle anabolism.
    AJP Endocrinology and Metabolism 11/2013; 306(2). DOI:10.1152/ajpendo.00440.2013 · 4.09 Impact Factor
  • P J Atherton, B E Phillips
    The Journal of Physiology 11/2013; 591(Pt 21):5267-8. DOI:10.1113/jphysiol.2013.265371 · 4.54 Impact Factor
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    ABSTRACT: Compromised limb blood flow in aging may contribute to the development of sarcopenia, frailty, and the metabolic syndrome. We developed a novel contrast-enhanced ultrasound technique using Sonovue™ to characterize muscle microvasculature responses to an oral feeding stimulus (15 g essential amino acids) in young (∼20 years) and older (∼70 years) men. Intensity-time replenishment curves were made via an ultrasound probe "fixed" over the quadriceps, with intermittent high mechanical index destruction of microbubbles within muscle vasculature. This permitted real-time measures of microvascular blood volume (MBV), microvascular flow velocity (MFV) and their product, microvascular blood flow (MBF). Leg blood flow (LBF) was measured by Doppler and insulin by enzyme-linked immunosorbent assay. Steady-state contrast concentrations needed for comparison between different physiological states were achieved <150 sec from commencing Sonovue™ infusion, and MFV and MBV measurements were completed <120 sec thereafter. Interindividual coefficients of variation in MBV and MFV were 35-40%, (N = 36). Younger men (N = 6) exhibited biphasic vascular responses to feeding with early increases in MBV (+36%, P < 0.008 45 min post feed) reflecting capillary recruitment, and late increases in MFV (+77%, P < 0.008) and MBF (+130%, P < 0.007 195 min post feed) reflecting more proximal vessel dilatation. Early MBV responses were synchronized with peak insulin but not increased LBF, while later changes in MFV and MBF occurred with insulin at post absorptive values but alongside increased LBF. All circulatory responses were absent in old men (N = 7). Thus, impaired postprandial circulation could impact age-related declines in muscle glucose disposal, protein anabolism, and muscle mass.
    10/2013; 1(5):e00119. DOI:10.1002/phy2.119
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    ABSTRACT: Focal adhesion kinase (FAK) is an attachment complex protein associated with the regulation of muscle mass, through as of yet unclear mechanisms. We tested whether FAK is functionally important for muscle hypertrophy, with the hypothesis that FAK knockdown (FAK-KD) would impede cell growth associated with a trophic stimulus. C2C12 skeletal muscle cells harbouring FAK targeted (FAK-KD) or scrambled (SCR) shRNA were created using lentiviral transfection techniques. Both FAK-KD and SCR myotubes were incubated for 24 h with IGF-1 (10 ng.ml(-1)) and additional SCR cells (± IGF-1) were incubated with a FAK-kinase inhibitor before assay of cell growth. Muscle protein synthesis (MPS) and putative FAK signalling mechanisms (immunoblotting and co-immunoprecipitation) were assessed. IGF-1-induced increases in myotube width (+41±7% vs. non-IGF-1-treated) and total protein (+44±6%) were, after 24 h, attenuated in FAK-KD cells while MPS was suppressed in FAK-KD vs. SCR after 4 h. These blunted responses were associated with attenuated IGF-1-induced FAK Tyr397 phosphorylation, and markedly suppressed phosphorylation of tuberous sclerosis complex 2 (TSC2) and critical downstream mTOR signalling (ribosomal S6 kinase, eIF4F assembly) in FAK shRNA cells (all P<0.05 vs. IGF-1-treated SCR cells). However, binding of FAK to TSC2 or its phosphatase Shp-2 was not affected by IGF-1 or cell phenotype. Finally, FAK-KD mediated suppression of cell growth was recapitulated by direct inhibition of FAK kinase activity in SCR cells. We conclude that FAK is required for IGF-1-induced muscle hypertrophy, through a TSC2-mTOR-S6K1-dependent pathway via means requiring the kinase activity of FAK, but not altered FAK-TSC2 or FAK-Shp-2 binding.
    AJP Endocrinology and Metabolism 05/2013; 305(2). DOI:10.1152/ajpendo.00541.2012 · 4.09 Impact Factor
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    ABSTRACT: Skeletal muscle structure and function are markedly affected by chronic disuse. With unloading, muscle mass is lost at rate of about 0.4 %/day but little is known about the recovery of muscle mass and strength following disuse. Here we report an extensive data set describing in detail skeletal muscle adaptations in structure and function in response to both disuse and retraining. Eight young men (23 ± 2.2 years) underwent 3 weeks of unilateral lower limb suspension (ULLS) followed by a 3-week resistance training recovery program. Knee extensor isometric torque, voluntary activation, quadriceps femoris (QF) muscle volume (QFvol), fascicle length (Lf) and pennation angle (θ), physiological cross-sectional area (PCSA) of all four heads of the QF muscle, were measured before, after ULLS, and post-ULLS-resistance training. Needle biopsies were taken from the vastus lateralis muscle of a subgroup (n = 6) of the same subjects and cross sectional area of individual muscle s and myosin content of muscle samples were determined. Following 3 weeks of ULLS, isometric torque decreased by 26 %, PCSA by 3 %, QFvol by 10 %. Lf and θ of all four heads of QF significantly decreased (p ≤ 0.05). Following the 3-week retraining period, isometric torque, PCSA, QFvol, Lf and θ of all four heads of QF were all fully restored to pre ULLS values. CSA of individual muscle fibres and myosin content of muscle samples decreased by 26 and 35 % respectively (post-ULLS) and recovered to almost pre-ULLS values following retraining. There were no significant changes in voluntary activation of the quadriceps muscles in response to either ULLS or subsequent retraining. These results indicate that: (1) the loss of muscle force with 3-week unloading in humans is mostly explained by muscle atrophy and by a decrease in myosin content and, (2) all the neuromuscular changes induced by this model of disuse can be fully restored after a resistance training intervention of equal duration.
    Biogerontology 05/2013; DOI:10.1007/s10522-013-9427-6 · 3.01 Impact Factor
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    ABSTRACT: Background:Alterations in muscle protein metabolism underlie age-related muscle atrophy. During periods of muscle disuse, muscle protein synthesis is blunted and muscle atrophy occurs in young and old. The impact of a short reduction in physical activity on muscle protein metabolism in older adults is unknown.Purpose:To investigate the impact of 14 days of reduced daily steps on fasted and fed-state rates of myofibrillar protein synthesis (MPS) to provide insight into the mechanisms for changes in muscle mass and markers of metabolic health.Methods:Prior to and following 14 d of reduced daily step-count, ten, healthy older adults (72±1 yr) underwent measures of insulin sensitivity, muscle strength, physical function and body composition. Using a primed constant infusion of L-[ring-(13)C6] phenylalanine with serial muscle biopsies, basal, postabsorptive and postprandial rates of MPS were determined before and after the 14 d intervention.Results:Daily step-count was reduced by ∼76% to 1413±110 steps/d. Leg fat-free mass was reduced by ∼3.9% (P < 0.001). Postabsorptive insulin resistance was increased by ∼12% and postprandial insulin sensitivity reduced by ∼43% following step-reduction (P < 0.005). Concentrations of TNF-α and CRP were increased by ∼12 and 25%, respectively, following step-reduction (P < 0.05). Postprandial rates of MPS were reduced by ∼26% following the intervention (P = 0.028) with no difference in postabsorptive rates.Conclusion:The present study demonstrates that 14 days of reduced steps in older adults induces small but measurable reductions in muscle mass that appear to be underpinned by reductions in post-prandial MPS and are accompanied by impairments in insulin sensitivity and systemic inflammatory markers and postprandial MPS.
    The Journal of Clinical Endocrinology and Metabolism 04/2013; 98(6). DOI:10.1210/jc.2013-1502 · 6.31 Impact Factor
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    ABSTRACT: Maintenance of skeletal muscle mass is contingent upon the dynamic equilibrium (fasted losses-fed gains) in protein turnover. Of all nutrients, the single amino acid Leucine (Leu) possesses the most marked anabolic characteristics in acting as a trigger element for the initiation of protein synthesis. While the mechanisms by which Leu is "sensed" have been the subject of great scrutiny, as a branched-chain amino acid, Leu can be catabolized within muscle, thus posing the possibility that metabolites of Leu could be involved in mediating the anabolic effect(s) of Leu. Our objective was to measure muscle protein anabolism in response to Leu and its metabolite HMB. Using [1,2-13C2]Leu and [2H5]phenylalanine tracers, and GC-MS/GC-C-IRMS we studied the effect of HMB or Leu alone on MPS (by tracer incorporation into myofibrils), and for HMB we also measured muscle proteolysis (by A-V dilution). Orally consumed 3.42g free-acid (FA-HMB) HMB (providing 2.42g of pure HMB) exhibited rapid bioavailability in plasma and muscle and, similarly to 3.42g Leu, stimulated MPS (HMB: +70% vs. Leu: +110 %). While HMB and Leu both increased anabolic signaling (mechanistic target of rapamycin; mTOR), this was more pronounced with Leu (i.e., p70S6K1 signaling ≤90 min vs. ≤30 min for HMB). HMB consumption also attenuated MPB (-57 %) in an insulin-independent manner. We conclude that exogenous HMB induces acute muscle anabolism (increased MPS and reduced MPB) albeit perhaps via distinct, and/or additional mechanism(s) to Leu.
    The Journal of Physiology 04/2013; 591(11). DOI:10.1113/jphysiol.2013.253203 · 4.54 Impact Factor

Publication Stats

3k Citations
304.40 Total Impact Points

Institutions

  • 2007–2015
    • University of Nottingham
      • • School of Medicine
      • • School of Graduate Entry Medicine and Health
      • • School of Biomedical Sciences
      Nottigham, England, United Kingdom
    • University of Derby
      Derby, England, United Kingdom
  • 2012
    • Aintree University Hospital NHS Foundation Trust
      Liverpool, England, United Kingdom
  • 2009
    • The University of Edinburgh
      Edinburgh, Scotland, United Kingdom
  • 2008
    • University of Aberdeen
      • Institute of Medical Sciences
      Aberdeen, Scotland, United Kingdom
  • 2004–2006
    • University of Central Lancashire
      Preston, England, United Kingdom