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

1998 ◽  
Vol 85 (5) ◽  
pp. 1744-1752 ◽  
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.

Changes in leucine kinetics during meal absorption: effects of dietary leucine availability

1986 ◽  
Vol 250 (6) ◽  
pp. E695-E701 ◽  
Author(s):  
S. Nissen ◽  
M. W. Haymond
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Branched Chain Amino Acids ◽  
Whole Body ◽  
Constant Infusion ◽  
Leucine Oxidation ◽  
Amino Acid Availability ◽  
Dietary Amino Acid ◽  
Branched Chain

Whole-body leucine and alpha-ketoisocaproate (KIC) metabolism were estimated in mature dogs fed a complete meal, a meal devoid of branched-chain amino acids, and a meal devoid of all amino acids. Using a constant infusion of [4,5-3H]leucine and alpha-[1-14C]ketoisocaproate (KIC), combined with dietary [5,5,5-2H3]leucine, the rate of whole-body proteolysis, protein synthesis, leucine oxidation, and interconversion of leucine and KIC were estimated along with the rate of leucine absorption. Ingestion of the complete meal resulted in a decrease in the rate of endogenous proteolysis, a small increase in the estimated rate of leucine entering protein, and a twofold increase in the rate of leucine oxidation. Ingestion of either the meal devoid of branched-chain amino acids or devoid of all amino acids resulted in a decrease in estimates of whole-body rates of proteolysis and protein synthesis, decreased leucine oxidation, and a decrease in the interconversion of leucine and KIC. The decrease in whole-body proteolysis was closely associated with the rise in plasma insulin concentrations following meal ingestion. Together these data suggest that the transition from tissue catabolism to anabolism is the result, at least in part, of decreased whole-body proteolysis. This meal-related decrease in proteolysis is independent of the dietary amino acid composition or content. In contrast, the rate of protein synthesis was sustained only when the meal complete in all amino acids was provided, indicating an overriding control of protein synthesis by amino acid availability.

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

1994 ◽  
Vol 266 (3) ◽  
pp. F432-F438 ◽  
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.

scholarly journals Impact of Growth Hormone and Dehydroepiandrosterone on Protein Metabolism in Glucocorticoid-Treated Patients

2008 ◽  
Vol 93 (3) ◽  
pp. 688-695 ◽  
Author(s):  
Morton G. Burt ◽  
Gudmundur Johannsson ◽  
A. Margot Umpleby ◽  
Donald J. Chisholm ◽  
Ken K. Y. Ho
Keyword(s):  
Protein Metabolism ◽  
Dose Finding ◽  
Whole Body ◽  
Constant Infusion ◽  
Leucine Incorporation ◽  
Protein Loss ◽  
Body Protein ◽  
Prednisone Dose ◽  
Leucine Oxidation

Abstract Context: Chronic pharmacological glucocorticoid (GC) use causes substantial morbidity from protein wasting. GH and androgens are anabolic agents that may potentially reverse GC-induced protein loss. Objective: Our objective was to assess the effect of GH and dehydroepiandrosterone (DHEA) on protein metabolism in subjects on long-term GC therapy. Design: This was an open, stepwise GH dose-finding study (study 1), followed by a randomized cross-over intervention study (study 2). Setting: The studies were performed at a clinical research facility. Patients and Intervention: In study 1, six subjects (age 69 ± 4 yr) treated with long-term (&gt;6 months) GCs (prednisone dose 8.3 ± 0.8 mg/d) were studied before and after two sequential GH doses (0.8 and 1.6 mg/d) for 2 wk each. In study 2, 10 women (age 71 ± 3 yr) treated with long-term GCs (prednisone dose 5.4 ± 0.5 mg/d) were studied at baseline and after 2-wk treatment with GH 0.8 mg/d, DHEA 50 mg/d, or GH and DHEA (combination treatment). Main Outcome Measure: Changes in whole body protein metabolism were assessed using a 3-h primed constant infusion of 1-[13C]leucine, from which rates of leucine appearance, leucine oxidation, and leucine incorporation into protein were estimated. Results: In study 1, GH 0.8 and 1.6 mg/d significantly reduced leucine oxidation by 19% (P = 0.03) and 31% (P = 0.02), and increased leucine incorporation into protein by 10% (P = 0.13) and 19% (P = 0.04), respectively. The lower GH dose did not cause hyperglycemia, whereas GH 1.6 mg/d resulted in fasting hyperglycemia in two of six subjects. In study 2, DHEA did not significantly change leucine metabolism alone or when combined with GH. Blood glucose was not affected by DHEA. Conclusion: GH, at a modest supraphysiological dose of 0.8 mg/d, induces protein anabolism in chronic GC users without causing diabetes. DHEA 50 mg/d does not enhance the effect of GH. GH may safely prevent or reverse protein loss induced by chronic GC therapy.

Dietary Protein Does Not Impact Whole Body Protein Turnover During an Exercise Induced Energy Deficit

2007 ◽  
Vol 39 (Supplement) ◽  
pp. S83
Author(s):  
Matthew A. Pikosky ◽  
Tracey J. Smith ◽  
Lauri Byerley ◽  
Ann Grediagin ◽  
Carmen Castaneda-Sceppa ◽  
...  
Keyword(s):  
Dietary Protein ◽  
Protein Turnover ◽  
Energy Deficit ◽  
Whole Body ◽  
Body Protein ◽  
Exercise Induced

Comparison of 15N-Labelled Glycine, Aspartate, Valine and Leucine for Measurement of Whole-Body Protein Turnover

1979 ◽  
Vol 57 (3) ◽  
pp. 281-283 ◽  
Author(s):  
M. Taruvinga ◽  
A. A. Jackson ◽  
M. H. N. Golden
Keyword(s):  
Amino Acids ◽  
Protein Turnover ◽  
Ammonia Nitrogen ◽  
Whole Body ◽  
Constant Infusion ◽  
Turnover Rates ◽  
Body Protein ◽  
End Products ◽  
Lower Protein ◽  
Branched Chain

1. Whole-body protein turnover was measured in rats by constant infusion of 15N-labelled glycine, aspartate, valine and leucine and measuring the enrichment of hepatic and renal urea and ammonia nitrogen. 2. The values obtained with [15N]glycine were comparable with values reported with methods based on different assumptions. 3. [15N]Aspartate gave rise to an increased enrichment of urea and ammonia and hence to lower protein-turnover rates. 4. [15N]Valine and [15N]leucine gave low enrichments of nitrogenous end products and hence to high protein-turnover rates. 5. All 15N-labelled amino acids are not equally suitable for measuring whole-body protein turnover by the end-product method. The relative amounts of 15N going to the end products can be predicted from the known individual metabolism of aspartate and the branched-chain amino acids.

Evaluation of protein requirements for trained strength athletes

1992 ◽  
Vol 73 (5) ◽  
pp. 1986-1995 ◽  
Author(s):  
M. A. Tarnopolsky ◽  
S. A. Atkinson ◽  
J. D. MacDougall ◽  
A. Chesley ◽  
S. Phillips ◽  
...  
Keyword(s):  
Protein Intake ◽  
Dietary Treatment ◽  
Whole Body ◽  
Body Density ◽  
Body Protein ◽  
Creatinine Excretion ◽  
Protein Requirements ◽  
Leucine Oxidation ◽  
Low Protein ◽  
Sedentary Subjects

Leucine kinetic and nitrogen balance (NBAL) methods were used to determine the dietary protein requirements of strength athletes (SA) compared with sedentary subjects (S). Individual subjects were randomly assigned to one of three protein intakes: low protein (LP) = 0.86 g protein.kg-1.day-1, moderate protein (MP) = 1.40 g protein.kg-1.day-1, or high protein (HP) = 2.40 g protein.kg-1.day-1 for 13 days for each dietary treatment. NBAL was measured and whole body protein synthesis (WBPS) and leucine oxidation were determined from L-[1–13C]leucine turnover. NBAL data were used to determine that the protein intake for zero NBAL for S was 0.69 g.kg-1.day-1 and for SA was 1.41 g.kg-1.day-1. A suggested recommended intake for S was 0.89 g.kg-1.day-1 and for SA was 1.76 g.kg-1.day-1. For SA, the LP diet did not provide adequate protein and resulted in an accommodated state (decreased WBPS vs. MP and HP), and the MP diet resulted in a state of adaptation [increase in WBPS (vs. LP) and no change in leucine oxidation (vs. LP)]. The HP diet did not result in increased WBPS compared with the MP diet, but leucine oxidation did increase significantly, indicating a nutrient overload. For S the LP diet provided adequate protein, and increasing protein intake did not increase WBPS. On the HP diet leucine oxidation increased for S. These results indicated that the MP and HP diets were nutrient overloads for S. There were no effects of varying protein intake on indexes of lean body mass (creatinine excretion, body density) for either group. In summary, protein requirements for athletes performing strength training are greater than for sedentary individuals and are above current Canadian and US recommended daily protein intake requirements for young healthy males.

TNF directly stimulates glucose uptake and leucine oxidation and inhibits FFA flux in conscious dogs

1996 ◽  
Vol 270 (5) ◽  
pp. E864-E872 ◽  
Author(s):  
Y. Sakurai ◽  
X. J. Zhang ◽  
R. R. Wolfe
Keyword(s):  
Glucose Production ◽  
Baseline Period ◽  
Endogenous Glucose Production ◽  
Whole Body ◽  
Constant Infusion ◽  
Direct Effects ◽  
Body Protein ◽  
Leucine Oxidation ◽  
Period 2 ◽  
Plasma Ffa

We tested the hypothesis that the metabolic changes in glucose, lipid, and protein metabolism seen during tumor necrosis factor (TNF) infusion were due to the increase in plasma glucagon concentration rather than to the direct effects of TNF. We employed a pancreatic clamp technique to keep plasma insulin and glucagon concentrations constant throughout a 4-h isotope infusion. Glucose, lipid, and protein kinetics were measured by means of the primed, constant infusion of [6,6-2H]glucose, [2H5]glycerol, [2H2]palmitic acid, and [1-13C]leucine. After a 2-h baseline period (period 1), TNF was infused as a primed, constant infusion (prime, 2.5 micrograms/kg; constant infusion, 62.5 ng.kg-1.min-1) for 2 h (period 2). Whereas plasma glucose concentration dropped significantly during TNF infusion, endogenous glucose production did not change. The decrease in glucose concentrations was due to a stimulation of glucose clearance (P < 0.05). The rate of lipolysis did not decrease significantly, but free fatty acid (FFA) flux and plasma FFA concentration significantly decreased during TNF infusion (P < 0.05). The rate of appearance of leucine was not affected by TNF infusion, but TNF caused a significant increase in 13CO2 excretion (P < 0.05) and leucine oxidation (P < 0.05). The calculated rates of whole body protein synthesis decreased. We concluded that TNF did not directly affect glucose production. Furthermore, changes in protein and lipid kinetics during TNF infusion were not mediated by changes in insulin or glucagon and may have reflected direct effects of TNF.

scholarly journals Effect of dietary protein on energy metabolism including protein synthesis in the spiny lobster Sagmariasus verreauxi

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuangyao Wang ◽  
Chris G. Carter ◽  
Quinn P. Fitzgibbon ◽  
Basseer M. Codabaccus ◽  
Gregory G. Smith
Keyword(s):  
Protein Synthesis ◽  
Energy Metabolism ◽  
Dietary Protein ◽  
Spiny Lobster ◽  
Ammonia Excretion ◽  
Metabolic Energy ◽  
Whole Body ◽  
Body Protein ◽  
Energy Substrate ◽  
Sagmariasus Verreauxi

AbstractThis is the first study in an aquatic ectotherm to combine a stoichiometric bioenergetic approach with an endpoint stochastic model to explore dietary macronutrient content. The combination of measuring respiratory gas (O2 and CO2) exchange, nitrogenous (ammonia and urea) excretion, specific dynamic action (SDA), metabolic energy substrate use, and whole-body protein synthesis in spiny lobster, Sagmariasus verreauxi, was examined in relation to dietary protein. Three isoenergetic feeds were formulated with varying crude protein: 40%, 50% and 60%, corresponding to CP40, CP50 and CP60 treatments, respectively. Total CO2 and ammonia excretion, SDA magnitude and coefficient, and protein synthesis in the CP60 treatment were higher compared to the CP40 treatment. These differences demonstrate dietary protein influences post-prandial energy metabolism. Metabolic use of each major energy substrate varied at different post-prandial times, indicating suitable amounts of high-quality protein with major non-protein energy-yielding nutrients, lipid and carbohydrate, are critical for lobsters. The average contribution of protein oxidation was lowest in the CP50 treatment, suggesting mechanisms underlying the most efficient retention of dietary protein and suitable dietary inclusion. This study advances understanding of how deficient and surplus dietary protein affects energy metabolism and provides approaches for fine-scale feed evaluation to support sustainable aquaculture.

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