Effects of dietary protein contents and habitual endurance exercise on supplemental leucine oxidation in mice

ABSTRACT Background Protein ingestion increases skeletal muscle protein synthesis rates during recovery from endurance exercise. Objectives We aimed to determine the effect of graded doses of dietary protein co-ingested with carbohydrate on whole-body protein metabolism, and skeletal muscle myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis rates during recovery from endurance exercise. Methods In a randomized, double-blind, parallel-group design, 48 healthy, young, endurance-trained men (mean ± SEM age: 27 ± 1 y) received a primed continuous infusion of l-[ring-2H5]-phenylalanine, l-[ring-3,5-2H2]-tyrosine, and l-[1-13C]-leucine and ingested 45 g carbohydrate with either 0 (0 g PRO), 15 (15 g PRO), 30 (30 g PRO), or 45 (45 g PRO) g intrinsically l-[1-13C]-phenylalanine and l-[1-13C]-leucine labeled milk protein after endurance exercise. Blood and muscle biopsy samples were collected over 360 min of postexercise recovery to assess whole-body protein metabolism and both MyoPS and MitoPS rates. Results Protein intake resulted in ∼70%–74% of the ingested protein-derived phenylalanine appearing in the circulation. Whole-body net protein balance increased dose-dependently after ingestion of 0, 15, 30, or 45 g protein (mean ± SEM: −0.31± 0.16, 5.08 ± 0.21, 10.04 ± 0.30, and 13.49 ± 0.55 μmol phenylalanine · kg−1 · h−1, respectively; P < 0.001). 30 g PRO stimulated a ∼46% increase in MyoPS rates (%/h) compared with 0 g PRO and was sufficient to maximize MyoPS rates after endurance exercise. MitoPS rates were not increased after protein ingestion; however, incorporation of dietary protein–derived l-[1-13C]-phenylalanine into de novo mitochondrial protein increased dose-dependently after ingestion of 15, 30, and 45 g protein at 360 min postexercise (0.018 ± 0.002, 0.034 ± 0.002, and 0.046 ± 0.003 mole percentage excess, respectively; P < 0.001). Conclusions Protein ingested after endurance exercise is efficiently digested and absorbed into the circulation. Whole-body net protein balance and dietary protein–derived amino acid incorporation into mitochondrial protein respond to increasing protein intake in a dose-dependent manner. Ingestion of 30 g protein is sufficient to maximize MyoPS rates during recovery from a single bout of endurance exercise. This trial was registered at trialregister.nl as NTR5111.

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Dietary protein, endurance exercise, and human skeletal-muscle protein turnover

Current Opinion in Clinical Nutrition & Metabolic Care ◽

10.1097/mco.0b013e3280115e3b ◽

2007 ◽

Vol 10 (1) ◽

pp. 40-45 ◽

Cited By ~ 33

Author(s):

Nancy R Rodriguez ◽

Lisa M Vislocky ◽

P Courtney Gaine

Keyword(s):

Skeletal Muscle ◽

Endurance Exercise ◽

Dietary Protein ◽

Protein Turnover ◽

Human Skeletal Muscle ◽

Muscle Protein ◽

Skeletal Muscle Protein ◽

Muscle Protein Turnover

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Endurance exercise training attenuates leucine oxidation and BCOAD activation during exercise in humans

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2000.278.4.e580 ◽

2000 ◽

Vol 278 (4) ◽

pp. E580-E587 ◽

Cited By ~ 116

Author(s):

Scott McKenzie ◽

Stuart M. Phillips ◽

Sherry L. Carter ◽

Stuart Lowther ◽

Martin J. Gibala ◽

...

Keyword(s):

Exercise Training ◽

Endurance Exercise ◽

Citrate Synthase ◽

Exercise Bout ◽

Leucine Oxidation ◽

Endurance Exercise Training ◽

Exercise Training Program ◽

Activated State ◽

Branched Chain ◽

Exercise In Humans

We studied the effects of a 38-day endurance exercise training program on leucine turnover and substrate metabolism during a 90-min exercise bout at 60% peak O2 consumption (V˙o 2 peak) in 6 males and 6 females. Subjects were studied at both the same absolute (ABS) and relative (REL) exercise intensities posttraining. Training resulted in a significant increase in whole bodyV˙o 2 peak and skeletal muscle citrate synthase (CS; P < 0.001), complex I-III ( P < 0.05), and total branched-chain 2-oxoacid dehydrogenase (BCOAD; P < 0.001) activities. Leucine oxidation increased during exercise for the pretraining trial (PRE, P < 0.001); however, there was no increase for either the ABS or REL posttraining trial. Leucine oxidation was significantly lower for females at all time points during rest and exercise ( P < 0.01). The percentage of BCOAD in the activated state was significantly increased after exercise for both the PRE and REL exercise trials, with the increase in PRE being greater ( P < 0.001) compared with REL ( P < 0.05). Females oxidized proportionately more lipid and less carbohydrate during exercise compared with males. In conclusion, we found that 38 days of endurance exercise training significantly attenuated both leucine oxidation and BCOAD activation during 90 min of endurance exercise at 60%V˙o 2 peak for both ABS and REL exercise intensities. Furthermore, females oxidize proportionately more lipid and less carbohydrate compared with males during endurance exercise.

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Estrogen Supplementation Reduces Leucine Oxidation at Rest and During Moderate Intensity Endurance Exercise in Men

Medicine & Science in Sports & Exercise ◽

10.1249/00005768-200405001-00929 ◽

2004 ◽

Vol 36 (Supplement) ◽

pp. S194

Author(s):

Mazen J. Hamadeh ◽

Michaela C. Devries ◽

Mark A. Tarnopolsky

Keyword(s):

Endurance Exercise ◽

Moderate Intensity ◽

Leucine Oxidation

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Estrogen Supplementation Reduces Leucine Oxidation at Rest and During Moderate Intensity Endurance Exercise in Men

Medicine & Science in Sports & Exercise ◽

10.1097/00005768-200405001-00929 ◽

2004 ◽

Vol 36 (Supplement) ◽

pp. S194

Author(s):

Mazen J. Hamadeh ◽

Michaela C. Devries ◽

Mark A. Tarnopolsky

Keyword(s):

Endurance Exercise ◽

Moderate Intensity ◽

Leucine Oxidation

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Metabolic responses to nephrosis: effect of a low-protein diet

AJP Renal Physiology ◽

10.1152/ajprenal.1994.266.3.f432 ◽

1994 ◽

Vol 266 (3) ◽

pp. F432-F438 ◽

Cited By ~ 2

Author(s):

E. J. Choi ◽

J. Bailey ◽

R. C. May ◽

T. Masud ◽

B. J. Maroni

Keyword(s):

Weight Loss ◽

Dietary Protein ◽

Protein Diet ◽

Nitrogen Excretion ◽

Whole Body ◽

Protein Catabolism ◽

Body Protein ◽

Leucine Oxidation ◽

Oxidation Rates ◽

And Control

To determine whether dietary protein restriction (LPD) causes protein catabolism in adriamycin nephrosis, nephrotic and control rats were paired by weight and gavage fed an 8.5% protein diet for 3 days (protocol 1) or 12 days (protocol 2). Fasting whole body protein turnover was then measured using a constant infusion of L-[1-14C]leucine. After 3 days of LPD, proteinuria decreased slightly and body weight did not change in either group. In contrast, leucine oxidation and urinary urea nitrogen excretion in nephrotic rats decreased by 18% and 37%, respectively (P < or = 0.05). After 12 days of LPD, weight loss did not differ between groups. In contrast to protocol 1, proteinuria decreased by 45% in nephrotic rats fed LPD for 12 days, and leucine oxidation rats increased to the level of control rats. Rates of whole body protein synthesis (PS) and degradation (PD) did not differ between nephrotic and control rats receiving LPD for 3 or 12 days, but were significantly lower than rates measured in rats fed 22% protein. We conclude that 1) proteinuria stimulates protein conservation even when dietary protein intake is restricted; 2) the decrease in amino acid oxidation was dependent on moderate proteinuria, since prolonged LPD ameliorated nephrosis and leucine oxidation rates increased to control levels; and 3) since weight loss and rates of whole body PS and PD in nephrotic and control animals were indistinguishable, moderate proteinuria did not increase protein catabolism.

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Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00060.2005 ◽

2005 ◽

Vol 289 (4) ◽

pp. E678-E683 ◽

Cited By ~ 52

Author(s):

Douglas R. Bolster ◽

Matthew A. Pikosky ◽

P. Courtney Gaine ◽

William Martin ◽

Robert R. Wolfe ◽

...

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Endurance Exercise ◽

Dietary Protein ◽

Protein Intake ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Dietary Protein Intake ◽

Skeletal Muscle Protein ◽

Skeletal Muscle Protein Synthesis

This investigation evaluated the physiological impact of different dietary protein intakes on skeletal muscle protein synthesis postexercise in endurance runners. Five endurance-trained, male runners participated in a randomized, crossover design diet intervention, where they consumed either a low (0.8 g/kg; LP)-, moderate (1.8 g/kg; MP)-, or high (3.6 g/kg; HP)-protein diet for 4 wk. Diets were designed to be eucaloric with carbohydrate, fat, and protein approximating 60, 30, and 10%; 55, 30, and 15%; and 40, 30, and 30% for LP, MP, and HP, respectively. Substrate oxidation was assessed via indirect calorimetry at 3 wk of the dietary interventions. Mixed-muscle protein fractional synthetic rate (FSR) was measured after an endurance run (75 min at 70% V̇o2 peak) using a primed, continuous infusion of [2H5]phenylalanine. Protein oxidation increased with increasing protein intake, with each trial being significantly different from the other ( P < 0.01). FSR after exercise was significantly greater for LP (0.083%/h) and MP (0.078%/h) than for HP (0.052%/h; P < 0.05). There was no difference in FSR between LP and MP. This is the first investigation to establish that habitual dietary protein intake in humans modulates skeletal muscle protein synthesis after an endurance exercise bout. Future studies directed at mechanisms by which level of protein intake influences skeletal muscle turnover are needed.

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Effect of Chronic Endurance Exercise on Retention of Dietary Protein

International Journal of Sports Medicine ◽

10.1055/s-2007-1024886 ◽

1989 ◽

Vol 10 (02) ◽

pp. 118-123 ◽

Cited By ~ 64

Author(s):

J. Friedman ◽

P. Lemon

Keyword(s):

Endurance Exercise ◽

Dietary Protein

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Modulation of whole body protein metabolism, during and after exercise, by variation of dietary protein

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.5.1744 ◽

1998 ◽

Vol 85 (5) ◽

pp. 1744-1752 ◽

Cited By ~ 53

Author(s):

J. L. Bowtell ◽

G. P. Leese ◽

K. Smith ◽

P. W. Watt ◽

A. Nevill ◽

...

Keyword(s):

Skeletal Muscle ◽

Dietary Protein ◽

Whole Body ◽

Constant Infusion ◽

Body Protein ◽

Leucine Oxidation ◽

Low Protein ◽

Branched Chain ◽

Exercise Induced ◽

Induced Changes

The aim of this study was to investigate dietary protein-induced changes in whole body leucine turnover and oxidation and in skeletal muscle branched chain 2-oxo acid dehydrogenase (BCOADH) activity, at rest and during exercise. Postabsorptive subjects received a primed constant infusion ofl-[1-13C,15N]leucine for 6 h, after previous consumption of a high- (HP; 1.8 g ⋅ kg−1 ⋅ day−1, n = 8) or a low-protein diet (LP; 0.7 g ⋅ kg−1 ⋅ day−1, n = 8) for 7 days. The subjects were studied at rest for 2 h, during 2-h exercise at 60% maximum oxygen consumption, then again for 2 h at rest. Exercise induced a doubling of both leucine oxidation from 20 μmol ⋅ kg−1 ⋅ h−1and BCOADH percent activation from 7% in all subjects. Leucine oxidation was greater before (+46%) and during (+40%, P < 0.05) the first hour of exercise in subjects consuming the HP rather than the LP diet, but there was no additional change in muscle BCOADH activity. The results suggest that leucine oxidation was increased by previous ingestion of an HP diet, attributable to an increase in leucine availability rather than to a stimulation of the skeletal muscle BCOADH activity.

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