Whole Body Leucine Kinetics and Fractional Quadriceps Muscle Synthetic Rate (MPSR) in Alcoholic Patients

1988 ◽  
Vol 75 (s19) ◽  
pp. 36P-36P
Author(s):  
P.J. Pacy ◽  
M Read ◽  
V. Preedy ◽  
T.J. Peters ◽  
D Halliday
Keyword(s):  
Quadriceps Muscle ◽  
Whole Body ◽  
Synthetic Rate ◽  
Leucine Kinetics

Effect of fetal growth on maternal protein metabolism in postabsorptive rat

1987 ◽  
Vol 252 (3) ◽  
pp. E380-E390 ◽  
Author(s):  
P. R. Ling ◽  
B. R. Bistrian ◽  
G. L. Blackburn ◽  
N. Istfan
Keyword(s):  
Protein Synthesis ◽  
Late Pregnancy ◽  
Essential Amino Acids ◽  
Whole Body ◽  
Efficient Utilization ◽  
Synthetic Rate ◽  
Leucine Kinetics ◽  
Degradation Rates ◽  
Fractional Synthetic Rate ◽  
Plasma Leucine

Rates of protein synthesis were measured in whole fetuses and maternal tissues at 17 and 20 days of gestation in postabsorptive rats using continuous infusion of L-[1–14C]leucine. Fetal protein degradation rates were derived from the fractional rates of synthesis and growth. Whole-body (plasma) leucine kinetics in the mother showed a significant reduction of the fraction of plasma leucine oxidized in the mothers bearing older fetuses, a slight increase in the plasma flux, with total leucine oxidation and incorporation into protein remaining similar at the two gestational ages. Estimates of fractional protein synthesis in maternal tissues revealed an increase in placental and hepatic rates at 20 days of gestation, whereas the fractional synthetic rate in muscle remained unchanged. A model for estimation of the redistribution of leucine between plasma and tissues is described in detail. This model revealed a more efficient utilization of leucine in fetal protein synthesis in comparison with other maternal tissues, a greater dependency of the fetus on plasma supply of leucine, and a significant increase (2-fold) in the release of leucine from maternal muscle as the fetal requirements increased proportionately with its size. The latter conclusion, supported by nitrogen analysis and the ratio of bound-to-free leucine in maternal tissues, confirms the importance of maternal stores in maintaining the homeostasis of essential amino acids during late pregnancy.

scholarly journals A single whole body vibration session influences quadriceps muscle strength, functional mobility and balance of elderly with osteopenia and/or osteoporosis? Pragmatic clinical trial

2019 ◽  
Vol 18 (1) ◽  
pp. 73-80
Author(s):  
Luanda Alves Xavier Ramos ◽  
François Talles Medeiros Rodrigues ◽  
Lívia Shirahige ◽  
Maria de Fátima Alcântara Barros ◽  
Antônio Geraldo Cidrão de Carvalho ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Muscle Strength ◽  
Whole Body Vibration ◽  
Quadriceps Muscle ◽  
Functional Mobility ◽  
Whole Body ◽  
Pragmatic Clinical Trial ◽  
Body Vibration ◽  
Quadriceps Muscle Strength

scholarly journals Protein quantity, not protein quality, accelerates whole-body leucine kinetics and the acute-phase response during acute infection in marasmic Malawian children

2004 ◽  
Vol 92 (4) ◽  
pp. 589-595 ◽  
Author(s):  
M. J. Manary ◽  
K. E. Yarasheski ◽  
S. Smith ◽  
E. T. Abrams ◽  
C. A. Hart
Keyword(s):  
Protein Content ◽  
G Protein ◽  
Acute Phase ◽  
Acute Phase Response ◽  
Protein Quality ◽  
Egg White ◽  
Whole Body ◽  
Leucine Kinetics ◽  
Quality Diet ◽  
Standard Protein

The present study compared leucine kinetics and acute-phase-protein concentrations in three groups of marasmic, acutely infected Malawian children fed one of three isoenergetic diets. These were: an enhanced-protein-quality diet (egg-white+tryptophan, providing 1.2 g protein/kg per d; n 14); an increased-protein-content diet (egg-white+tryptophan, providing 1·8 g protein/kg per d; n 14); a standard-protein diet (1·2 g milk protein/kg per d; n 25). The hypotheses tested were that children receiving a diet with more protein would have greater rates of non-oxidative leucine disposal and that children receiving an isonitrogenous diet with a higher protein quality would have lower rates of leucine oxidation. The children were studied after 24 h of therapy using standard [13C]leucine stable-isotope tracer techniques. The children receiving the higher-protein-content diet had greater leucine kinetic rates than those receiving the standard-protein-content diet; non-oxidative leucine disposal was 170 (SD 52) v. 122 (SD 30) μmol leucine/kg per h (P<0·01). Leucine oxidation was less in the children receiving the enhanced-protein-quality diet than in those receiving the standard-protein-quality diet; 34 (SD 12) v. 45 (SD 13) μmol leucine/kg per h (P<0·05). The children receiving the high-protein-content diet increased their serum concentration for five of six acute-phase proteins 24 h after starting therapy, while those receiving the standard-protein-content diet did not. These data suggest that there was greater whole-body protein synthesis, and a more vigorous acute-phase response associated with the higher-protein-content diet. The clinical benefits associated with a higher protein intake in marasmic, acutely infected children need further study.

Effects of acute creatine monohydrate supplementation on leucine kinetics and mixed-muscle protein synthesis

2001 ◽  
Vol 91 (3) ◽  
pp. 1041-1047 ◽  
Author(s):  
G. Parise ◽  
S. Mihic ◽  
D. MacLennan ◽  
K. E. Yarasheski ◽  
M. A. Tarnopolsky
Keyword(s):  
Protein Synthesis ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Fat Free Mass ◽  
Whole Body ◽  
Synthetic Rate ◽  
Fractional Synthetic Rate ◽  
Before And After ◽  
Total Creatine ◽  
Plasma Leucine

Creatine monohydrate (CrM) supplementation during resistance exercise training results in a greater increase in strength and fat-free mass than placebo. Whether this is solely due to an increase in intracellular water or whether there may be alterations in protein turnover is not clear at this point. We examined the effects of CrM supplementation on indexes of protein metabolism in young healthy men ( n = 13) and women ( n = 14). Subjects were randomly allocated to CrM (20 g/day for 5 days followed by 5 g/day for 3–4 days) or placebo (glucose polymers) and tested before and after the supplementation period under rigorous dietary and exercise controls. Muscle phosphocreatine, creatine, and total creatine were measured before and after supplementation. A primed-continuous intravenous infusion of l-[1-13C]leucine and mass spectrometry were used to measure mixed-muscle protein fractional synthetic rate and indexes of whole body leucine metabolism (nonoxidative leucine disposal), leucine oxidation, and plasma leucine rate of appearance. CrM supplementation increased muscle total creatine (+13.1%, P < 0.05) with a trend toward an increase in phosphocreatine (+8.8%, P = 0.09). CrM supplementation did not increase muscle fractional synthetic rate but reduced leucine oxidation (−19.6%) and plasma leucine rate of appearance (−7.5%, P < 0.05) in men, but not in women. CrM did not increase total body mass or fat-free mass. We conclude that short-term CrM supplementation may have anticatabolic actions in some proteins (in men), but CrM does not increase whole body or mixed-muscle protein synthesis.

Effect of hyperglucagonemia on whole-body leucine metabolism in immature pigs before and during a meal

1988 ◽  
Vol 254 (3) ◽  
pp. E372-E377
Author(s):  
P. Ostaszewski ◽  
S. Nissen
Keyword(s):  
Whole Body ◽  
Fasting State ◽  
Plasma Glucagon ◽  
Immature Female ◽  
Leucine Metabolism ◽  
Basal Period ◽  
Leucine Kinetics ◽  
Made In

Leucine metabolism was measured isotopically in 12 immature female pigs to assess the effect of acute hyperglucagonemia on leucine kinetics in both the fed and fasting states. After an overnight fast, immature pigs were infused with alpha-[3H]ketoisocaproate and [14C]leucine. After a 2-h equilibration period, an infusion of either saline or 7 pg.kg-1.min-1 of glucagon was begun, which increased plasma glucagon from approximately 140 to approximately 640 pg/ml and doubled the insulin concentrations. Two hours later, pigs were fed small meals to which [5,5,5-2H3]leucine was added to trace absorption. By subtracting absorption from total leucine flux, an estimate of endogenous proteolysis during the meal was made. In the fasting state, glucagon increased proteolysis, relative to controls, by approximately 20% (P less than 0.05) and increased oxidation by approximately 50% (P less than 0.05). No significant glucagon-related changes in any other flux parameters occurred in the fasting state. Ingestion of the meals caused oxidation to increase 41% in control animals, whereas in glucagon-infused animals, oxidation increased 84% (P less than 0.05 control vs. glucagon response to meal). Additionally, animals infused with glucagon suppressed endogenous proteolysis 43% after the meal compared with a 55% decrease in control animals (P less than 0.05 basal period vs. fed period). These data indicate that glucagon stimulates whole-body proteolysis in both the fasting and fed states.

Stimulation of cholesterol biosynthesis from acetate in rat liver and adrenals by whole body X-irradiation

1959 ◽  
Vol 196 (6) ◽  
pp. 1231-1237 ◽  
Author(s):  
R. Gordon Gould ◽  
Virginia L. Bell ◽  
Edith H. Lilly
Keyword(s):  
Rat Liver ◽  
Adrenal Glands ◽  
Cholesterol Biosynthesis ◽  
Whole Body ◽  
Hepatic Cholesterol ◽  
Reliable Measure ◽  
Proximate Cause ◽  
Synthetic Rate ◽  
X Irradiation ◽  
Stimulation Of

Whole body x-irradiation resulted in an increased cholesterol biosynthesis in rat liver and adrenal glands, as measured by the rate of incorporation of either acetate-1-C14 or H3OH in intact animals. The effect was significant 24 hours postirradiation but was much larger at 48 hours, and was proportional to dosage over the range 300–2400 r. In liver the increase in rate was about 100%/100 r. Intestine showed no effect and carcass only a slight increase. Mice showed a small increase in hepatic cholesterol biosynthesis but rabbits and guinea pigs no significant change. Rats injected with both acetate-1-C14 and H3OH gave reasonably constant ratios of C14 and H3 in liver and carcass cholesterol in control and irradiated animals, supporting the hypothesis that the use of acetate-1-C14 in whole animals under standard conditions is a reliable measure of cholesterol biosynthetic rate. The proximate cause of the increased rate of cholesterol synthesis is postulated to be the decreased concentration; in liver a decrease of 0.12 mg/gm was correlated with a doubling of the synthetic rate.

Effect of hyperinsulinemia on ovine fetal leucine kinetics during prolonged maternal fasting

1992 ◽  
Vol 263 (4) ◽  
pp. E696-E702 ◽  
Author(s):  
E. A. Liechty ◽  
D. W. Boyle ◽  
H. Moorehead ◽  
Y. M. Liu ◽  
S. C. Denne
Keyword(s):  
Protein Metabolism ◽  
Glucose Utilization ◽  
Whole Body ◽  
Postnatal Life ◽  
Body Protein ◽  
Leucine Oxidation ◽  
Leucine Kinetics ◽  
Ovine Fetus ◽  
Ovine Fetal

The primary effect of insulin on whole body protein metabolism in postnatal life is to reduce proteolysis. To assess the role of insulin in the regulation of protein metabolism in prenatal life, leucine kinetics were determined in the ovine fetus at baseline and in response to hyperinsulinemia. These measurements were made in each fetus in two different maternal states: ad libitum maternal feeding and after a 5-day maternal fast. Maternal fasting resulted in significant increases in baseline fetal leucine rate of appearance (Ra; 51.9 +/- 16.7 vs. 37.3 +/- 3.6 mumol/min, P < 0.05) and leucine oxidation (30.1 +/- 8.9 vs. 8.8 +/- 2.2 mumol/min, P < 0.05). Hyperinsulinemia, which was associated with significant increases in fetal glucose utilization, did not affect total fetal leucine R(a) or leucine release from fetal proteolysis in either maternal state. Under well-fed maternal conditions, hyperinsulinemia produced no changes in the fetal oxidative or nonoxidative disposal of leucine. In contrast, during maternal fasting, hyperinsulinemia reduced fetal leucine oxidation (11.0 +/- 3.7 vs. 31.1 +/- 8.9 mumol/min, P < 0.05) and increased the nonoxidative disposal of leucine (35.4 +/- 4.0 vs. 19.0 +/- 6.1 mumol/min, P < 0.05). This resulted in a change in the fetal leucine accretion rate from negative to positive (-20.9 +/- 7.5 vs. 7.5 +/- 6.7 mumol/min, P < 0.05). These results suggest that, under conditions of restricted maternal substrate intake, fetal hyperinsulinemia and the attendant increase in fetal glucose utilization are associated with increased protein synthesis rather than decreased protein breakdown, thereby improving fetal leucine carcass accretion.

Skeletal muscle myosin heavy-chain synthesis rate in healthy humans

1997 ◽  
Vol 272 (1) ◽  
pp. E45-E50 ◽  
Author(s):  
P. Balagopal ◽  
O. Ljungqvist ◽  
K. S. Nair
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Muscle Protein ◽  
Mechanical Energy ◽  
Whole Body ◽  
Synthesis Rate ◽  
Tissue Fluid ◽  
Skeletal Muscle Myosin ◽  
Body Protein ◽  
Synthetic Rate

Mixed muscle protein synthetic rate has been measured in humans. These measurements represent the average of synthetic rates of all muscle proteins with variable rates. We determined to what extent the synthesis rate of mixed muscle protein in humans reflects that of myosin heavy chain (MHC), the main contractile protein responsible for the conversion of ATP to mechanical energy as muscle contraction. Fractional synthetic rates of MHC and mixed muscle protein were measured from the increment of [13C]leucine in these proteins in vastus lateralis biopsy samples taken at 5 and 10 h during a primed continuous infusion of L-[1-13C]leucine in 10 young healthy subjects. Calculations were done by use of plasma [13C]ketoisocaproate (KIC) and muscle tissue fluid [13C]leucine as surrogate measures of leucyl-tRNA. Fractional synthetic rate of MHC with plasma KIC (0.0299 +/- 0.0043%/h) and tissue fluid leucine (0.0443 +/- 0.0056%/h) were only 72 +/- 3% of that of mixed muscle protein (0.0408 +/- 0.0032 and 0.0603 +/- 0.0059%/h, respectively, with KIC and tissue fluid leucine). Contribution of MHC (7 +/- 1 mg.kg-1.h-1) to synthetic rates of whole body mixed muscle protein (36 +/- 5 mg.kg-1.h-1) and whole body protein (127 +/- 4 mg.kg-1.h-1) is only 18 +/- 1 and 5 +/- 1%, respectively. This relatively low contribution of MHC to whole body and mixed muscle protein synthesis warrants direct measurement of synthesis rate of MHC in conditions involving abnormalities of muscle contractile function.

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