scholarly journals Fractional catabolic rates of myosin and actin estimated by urinary excretion of NT-methylhistidine: the effect of dietary protein level on catabolic rates under conditions of restricted food intake

1977 ◽  
Vol 37 (3) ◽  
pp. 345-353 ◽  
Author(s):  
N. Nishizawa ◽  
M. Shimbo ◽  
S. Hareyama ◽  
R. Funabiki
Keyword(s):  
Skeletal Muscle ◽  
Urinary Excretion ◽  
Dietary Protein ◽  
Protein Level ◽  
Protein Intake ◽  
The Body ◽  
Dietary Protein Intake ◽  
Adult Rats ◽  
Critical Studies ◽  
Dietary Protein Level

1. Critical studies on the distribution of NT-methylhistidine (3-methylhistidine; Me-His) among organs and tissues in adult rats are reported. Adult rats contained 46.5 ± 3.6 mg Me-His/kg body-weight. Almost 90% of the Me-His in the body was recovered from skeletal muscle. These results support the hypothesis that fractional catabolic rates of myosin and actin in skeletal muscle can be estimated by measuring urinary excretion of Me-His.2. Dietary protein level did not affect the total amount of Me-His in the body. However, urinary excretion of Me-His increased as dietary protein intake was increased.3. From these results it was concluded that fractional catabolic rates of myosin and actin increase as dietary protein intake increases.

scholarly journals Effect of varying energy and protein intake on nitrogen balance in adults engaged in heavy manual labour

1979 ◽  
Vol 41 (1) ◽  
pp. 19-25 ◽  
Author(s):  
A. Iyengar ◽  
B. S. Narasinga Rao
Keyword(s):  
Urinary Excretion ◽  
Nitrogen Balance ◽  
Dietary Protein ◽  
Protein Level ◽  
Protein Intake ◽  
Energy Levels ◽  
Adult Men ◽  
Dietary Protein Level ◽  
Low Protein ◽  
Manual Labour

1. The effect of varying energy and protein intake on nitrogen balance in adult men engaged in heavy manual labour was investigated.2. Low protein and energy levels resulted in negative N balance and urea index (Waterlow, 1963) was decreased.3. Urinary excretion of hydroxyproline was found to be sensitive to dietary protein level, but not to energy.

scholarly journals PSIII-27 Dietary intakes of protein and starch affect the oxidation of nutrients in tissues of Largemouth bass

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 275-275
Author(s):  
Xinyu Li ◽  
Guoyao Wu
Keyword(s):  
Skeletal Muscle ◽  
Dietary Protein ◽  
Largemouth Bass ◽  
Protein Intake ◽  
Micropterus Salmoides ◽  
Nitrogen Retention ◽  
Dietary Protein Intake ◽  
Dietary Intakes ◽  
Protein Levels ◽  
Energy Retention

Abstract Largemouth bass (LMB, Micropterus salmoides) is a carnivorous fish. This study was conducted to test the hypothesis that dietary intakes of protein and starch affect the oxidation of nutrients in the intestine, liver, skeletal muscle and kidneys of LMB. Juvenile LMB (average initial weight = 18 g) were fed, for 8 weeks, fish meal- and soy protein concentrate-based diets containing 40%, 45% and 50% crude protein. The three isocaloric diets contained 22.3%, 15.78% and 9.2% dextrinized starch, respectively. The growth performance, energy retention, and lipid retention in LMB increased (P < 0.05) with increasing dietary protein levels, but the efficiency of nitrogen retention did not differ (P > 0.05) among the three groups of fish. Rates of oxidation of 2 mM glutamate and glutamine in the intestine were reduced (P < 0.05) in response to increased dietary protein intake. This adaptive metabolic change likely helps to prevent excessive production of ATP by the gut when the dietary provision of glutamate and glutamine was increased. Increasing dietary protein intake did not affect (P > 0.05) glutamate oxidation in the liver, kidneys or skeletal muscle, or glutamine oxidation in the muscle. In contrast, the rate of glutamine oxidation was increased (P < 0.05) in the liver but decreased (P < 0.05) in the kidneys as dietary protein intake was elevated from 40% to 50%. Rates of oxidation of 5 mM glucose were reduced (P < 0.05) in the liver, kidneys and intestine, but were not altered in skeletal muscle, in response to reduced starch intake. Rates of oxidation of 2 mM palmitate were reduced (P < 0.05) in the kidneys but were not influenced (P > 0.05) in the intestine, skeletal muscle or liver. We conclude that oxidation of energy substrates in LMB tissues is regulated by dietary protein and starch intake in a tissue-specific manner.

Dietary Protein Intake and Distribution Patterns of Well-Trained Dutch Athletes

2017 ◽  
Vol 27 (2) ◽  
pp. 105-114 ◽  
Author(s):  
Jenna B. Gillen ◽  
Jorn Trommelen ◽  
Floris C. Wardenaar ◽  
Naomi Y.J. Brinkmans ◽  
Joline J. Versteegen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Total Energy ◽  
Energy Intake ◽  
Dietary Protein ◽  
Adaptive Response ◽  
Protein Intake ◽  
Team Sport ◽  
Total Energy Intake ◽  
Food Sources ◽  
Dietary Protein Intake

Dietary protein intake should be optimized in all athletes to ensure proper recovery and enhance the skeletal muscle adaptive response to exercise training. In addition to total protein intake, the use of specific proteincontaining food sources and the distribution of protein throughout the day are relevant for optimizing protein intake in athletes. In the present study, we examined the daily intake and distribution of various proteincontaining food sources in a large cohort of strength, endurance and team-sport athletes. Well-trained male (n=327) and female (n=226) athletes completed multiple web-based 24-hr dietary recalls over a 2-4 wk period. Total energy intake, the contribution of animal- and plant-based proteins to daily protein intake, and protein intake at six eating moments were determined. Daily protein intake averaged 108±33 and 90±24 g in men and women, respectively, which corresponded to relative intakes of 1.5±0.4 and 1.4±0.4 g/kg. Dietary protein intake was correlated with total energy intake in strength (r=0.71, p <.001), endurance (r=0.79, p <.001) and team-sport (r=0.77, p <.001) athletes. Animal and plant-based sources of protein intake was 57% and 43%, respectively. The distribution of protein intake was 19% (19±8 g) at breakfast, 24% (25±13 g) at lunch and 38% (38±15 g) at dinner. Protein intake was below the recommended 20 g for 58% of athletes at breakfast, 36% at lunch and 8% at dinner. In summary, this survey of athletes revealed they habitually consume > 1.2 g protein/kg/d, but the distribution throughout the day may be suboptimal to maximize the skeletal muscle adaptive response to training.

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

2005 ◽  
Vol 289 (4) ◽  
pp. E678-E683 ◽  
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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