Leucine kinetics in endurance-trained humans

1990 ◽  
Vol 69 (1) ◽  
pp. 1-6 ◽  
Author(s):  
L. S. Lamont ◽  
D. G. Patel ◽  
S. C. Kalhan
Keyword(s):  
Energy Expenditure ◽  
Protein Turnover ◽  
Resting Energy Expenditure ◽  
Whole Body ◽  
Body Protein ◽  
Energy Expenditures ◽  
Leucine Kinetics ◽  
Constant Rate ◽  
Tracer Dilution ◽  
Resting Energy

This study compared whole-body leucine kinetics in endurance-trained (TRN) and sedentary (SED) control subjects. Eleven men and women (6 TRN, 5 SED) underwent a 6-h primed, constant-rate infusion of L-[1-13C]leucine. Leucine turnover and oxidation were measured using tracer dilution and by measuring 13C enrichment of expired CO2 combined with respiratory calorimetry. Whole-body leucine turnover was greater in the TRN subjects (P less than 0.004; TRN 98.3 +/- 5.0, SED 75.3 +/- 4.2 mumol.kg-1.h-1; mean +/- SE), but there was no difference between groups in leucine oxidation (TRN 13.1 +/- 0.97, SED 11.5 +/- 0.48 mumol.kg-1.h-1). Thus more leucine turnover was available for nonoxidative utilization. In addition, the TRN subjects had higher resting energy expenditures compared with the SED group, and when all subjects were included in the analysis, there was a significant correlation between energy expenditure and protein turnover (n = 11, R = 0.61, P = 0.05). Therefore the heightened resting energy expenditure in the TRN subjects may be accounted for by an increased whole-body protein turnover. These results suggest that endurance training results in increased leucine and/or protein turnover, which may contribute to the increased resting energy expenditure observed in these subjects.

scholarly journals Whole-body protein turnover and resting energy expenditure in obese, prepubertal children

1999 ◽  
Vol 69 (5) ◽  
pp. 857-862 ◽  
Author(s):  
Yves Schutz ◽  
Clara M Rueda-Maza ◽  
Marco Zaffanello ◽  
Claudio Maffeis
Keyword(s):  
Energy Expenditure ◽  
Protein Turnover ◽  
Resting Energy Expenditure ◽  
Whole Body ◽  
Body Protein ◽  
Prepubertal Children ◽  
Resting Energy

Whole body protein metabolism and resting energy expenditure in pregnant Gambian women

1992 ◽  
Vol 263 (4) ◽  
pp. E624-E631 ◽  
Author(s):  
L. Willommet ◽  
Y. Schutz ◽  
R. Whitehead ◽  
E. Jequier ◽  
E. B. Fern
Keyword(s):  
Protein Synthesis ◽  
Energy Expenditure ◽  
Protein Metabolism ◽  
Resting Energy Expenditure ◽  
First Trimester ◽  
Significant Rise ◽  
Whole Body ◽  
Body Protein ◽  
Fed State ◽  
Resting Energy

Whole body protein metabolism and resting energy expenditure (REE) were measured at 11, 23, and 33 wk of pregnancy in nine pregnant (not malnourished) Gambian women and in eight matched nonpregnant nonlactating (NPNL) matched controls. Rates of whole body nitrogen flux, protein synthesis, and protein breakdown were determined in the fed state from the level of isotope enrichment of urinary urea and ammonia during a period of 9 h after a single oral dose of [15N]glycine. At regular intervals, REE was measured by indirect calorimetry (hood system). Based on the arithmetic end-product average of values obtained with urea and ammonia, a significant increase in whole body protein synthesis was observed during the second trimester (5.8 +/- 0.4 g.kg-1.day-1) relative to values obtained both for the NPNL controls (4.5 +/- 0.3 g.kg-1.day-1) and those during the first trimester (4.7 +/- 0.3 g.kg-1.day-1). There was a significant rise in REE during the third trimester both in the preprandial and postprandial states. No correlation was found between REE after meal ingestion and the rate of whole body protein synthesis.

Protein and energy metabolism in chronic bacterial infection: studies in melioidosis

2000 ◽  
Vol 100 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Nicholas I. PATON ◽  
Brian ANGUS ◽  
Wipada CHAOWAGUL ◽  
Andrew J. SIMPSON ◽  
Yupin SUPUTTAMONGKOL ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Energy Expenditure ◽  
Bacterial Infection ◽  
Total Energy ◽  
Protein Turnover ◽  
Resting Energy Expenditure ◽  
Total Energy Expenditure ◽  
Whole Body ◽  
Anabolic Response ◽  
Resting Energy

Chronic infection is often accompanied by a wasting process, the metabolic basis of which is not fully understood. The aims of the present study were to measure protein and energy metabolism in patients with melioidosis (a serious and antibiotic-refractory Gram-negative bacterial infection which is endemic in South-East Asia) in order to define the metabolic abnormalities that might contribute to wasting. Whole-body protein turnover was measured using the [13C]leucine technique, both in the fasted state and while consuming a high-energy meal. Resting energy expenditure was measured by indirect calorimetry, and total energy expenditure by the bicarbonate/urea method. Results were normalized for fat-free mass, as estimated from skinfold thickness. Protein turnover was increased in melioidosis patients compared with healthy controls during fasting (170.9 compared with 124.1 µmol·kg-1·h-1; P = 0.04), but the net rate of catabolism (22.2 compared with 20.5 µmol·kg-1·h-1; P = 0.77) and the anabolic response to feeding were similar in the two groups. Resting energy expenditure was higher in melioidosis patients compared with controls (191.4 and 157.3 kJ·kg-1·day-1 respectively; P = 0.04), but total energy expenditure (measured in a separate group of eight patients with melioidosis) was low (192.1 kJ·kg-1·day-1). In conclusion, this study found no evidence of metabolic causative factors, such as accelerated net protein catabolism during fasting, a blunted anabolic response to feeding or increased daily energy expenditure, and therefore suggests that reduced energy intake is the prime cause of wasting. The observed normal response to feeding should encourage nutritional approaches to prevent wasting.

Whole Body Protein Turnover and Resting Metabolic Rate in Homozygous Sickle Cell Disease

1989 ◽  
Vol 77 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Asha Badaloo ◽  
Alan A. Jackson ◽  
Farook Jahoor
Keyword(s):  
Protein Synthesis ◽  
Energy Expenditure ◽  
Protein Turnover ◽  
Resting Metabolic Rate ◽  
Resting Energy Expenditure ◽  
Whole Body ◽  
Cell Disease ◽  
Nitrogen Flux ◽  
Body Protein ◽  
Homozygous Sickle Cell Disease

1. Whole body protein turnover and resting metabolic rate were measured in six adults with homozygous sickle cell disease (genotype HbSS) and in six normal adults (genotype HbAA) of similar age. 2. Turnover was measured with prime/intermittent oral doses of [15N]glycine over 18 h and resting energy expenditure was measured by indirect calorimetry. 3. In HbSS, nitrogen flux (0.9 ± 0.08 g day−1 kg−1), protein synthesis (6.0 ± 0.5 g day−1 kg−1) and protein degradation (5.6 ± 0.5 g day−1 kg−1) were significantly increased compared with HbAA nitrogen (flux 0.5 ± 0.02 g day−1 kg−1, protein synthesis 3.2 ± 0.2 g day−1 kg−1 and protein degradation 2.8 ± 0.2 g day−1 kg−1). 4. Resting energy expenditure was significantly higher in HbSS compared with HbAA when expressed per unit of body weight (115 ± 3 and 94 ± 4 kJ day−1 kg−1, respectively) or weight 0.75 (317 ± 6 and 269 ± 8 kJ day−1 kg−0.75, respectively). 5. The increase in protein turnover and energy expenditure suggest that patients with HbSS exist in a hypermetabolic state that requires greater dietary energy compared with HbAA.

scholarly journals Effects of a Caspase and a Calpain Inhibitor on Resting Energy Expenditures in Normal and Hypermetabolic Rats: a Pilot Study

2016 ◽  
pp. 537-541 ◽  
Author(s):  
P. G. VANA ◽  
H. M. LAPORTE ◽  
R. H. KENNEDY ◽  
R. L. GAMELLI ◽  
M. MAJETSCHAK
Keyword(s):  
Whole Body ◽  
Calpain Inhibitor ◽  
Protein Loss ◽  
Body Protein ◽  
Physiological Conditions ◽  
Energy Expenditures ◽  
Calpain Inhibitors ◽  
Caspase Cascades ◽  
Observation Period ◽  
Resting Energy

Several diseases induce hypermetabolism, which is characterized by increases in resting energy expenditures (REE) and whole body protein loss. Exaggerated protein degradation is thought to be the driving force underlying this response. The effects of caspase and calpain inhibitors on REE in physiological and hypermetabolic conditions, however, are unknown. Thus, we studied whether MDL28170 (calpain inhibitor) or z-VAD-fmk (caspase inhibitor) affect REE under physiological conditions and during hypermetabolism post-burn. Rats were treated five times weekly and observed for 6 weeks. Treatment was started 2 h (early) or 48 h (late) after burn. In normal rats, MDL28170 transiently increased REE to 130 % of normal during week 2-4. z-VAD-fmk reduced REE by 20-25 % throughout the observation period. Within 14 days after burns, REE increased to 130±5 %. Whereas MDL28170/early treatment did not affect REE, MDL28170/late transiently increased REE to 180±10 % of normal by week 4 post-burn. In contrast, with z-VAD-fmk/early REE remained between 90-110 % of normal post-burn. z-VAD-fmk/late did not affect burn-induced increases in REE. These data suggest that caspase cascades contribute to the development of hypermetabolism and that burn-induced hypermetabolism can be pharmacologically modulated. Our data point towards caspase cascades as possible therapeutic targets to attenuate hypermetabolism after burns, and possibly in other catabolic disease processes.

Advances in stable isotope tracer methodology part 2: new thoughts about an “old” method—measurement of whole body protein synthesis and breakdown in the fed state

2019 ◽  
Vol 68 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Robert R Wolfe ◽  
Sanghee Park ◽  
Il-Young Kim ◽  
Paul J Moughan ◽  
Arny A Ferrando
Keyword(s):  
Protein Synthesis ◽  
Dietary Protein ◽  
Protein Turnover ◽  
Peripheral Circulation ◽  
Whole Body ◽  
Balance Model ◽  
Body Protein ◽  
Fed State ◽  
Isotope Tracer ◽  
Tracer Dilution

Whole-body protein turnover (protein synthesis, breakdown, and net balance) model enables quantification of the response to a variety of circumstances, including the response to meal feeding. In the fed state, the whole-body protein turnover model requires taking account of the contribution of absorbed tracee to the observed total appearance of tracee in the peripheral blood (exogenous appearance, RaEXO). There are different approaches to estimating RaEXO. The use of an intrinsically labeled dietary protein is based on the overriding assumption that the appearance in the peripheral circulation of a tracer amino acid incorporated into a dietary protein is exactly proportional to the appearance of absorbed tracee. The bioavailability approach is based on the true ileal digestibility of the dietary protein and the irreversible loss of the tracee in the splanchnic bed via hydroxylation of the tracee (phenylalanine). Finally, RaEXO can be estimated as the increase above the basal rate of appearance of the tracee using traditional tracer dilution methodology. In this paper, we discuss the pros and cons of each approach and conclude that the bioavailability method is the least likely to introduce systematic errors and is therefore the preferable approach.

Accuracy and reliability of a portable indirect calorimeter compared to whole-body indirect calorimetry for measuring resting energy expenditure

2020 ◽  
Vol 39 ◽  
pp. 67-73 ◽  
Author(s):  
Sarah A. Purcell ◽  
Carlene Johnson-Stoklossa ◽  
Jenneffer Rayane Braga Tibaes ◽  
Alena Frankish ◽  
Sarah A. Elliott ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Indirect Calorimetry ◽  
Resting Energy Expenditure ◽  
Whole Body ◽  
Resting Energy

Whole Body Protein Metabolism in Human Pulmonary Tuberculosis and Undernutrition: Evidence for Anabolic Block in Tuberculosis

1998 ◽  
Vol 94 (3) ◽  
pp. 321-331 ◽  
Author(s):  
Derek C. MacAllan ◽  
Margaret A. McNurlan ◽  
Anura V. Kurpad ◽  
George De Souza ◽  
Prakash S. Shetty ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Body Mass ◽  
Protein Metabolism ◽  
Protein Turnover ◽  
Nutrition Support ◽  
Whole Body ◽  
Body Protein ◽  
Leucine Kinetics ◽  
Body Energy ◽  
Net Protein

1. Differing patterns of protein metabolism are seen in wasting due to undernutrition and wasting due to chronic infection. 2. We investigated whole body energy and protein metabolism in nine subjects with pulmonary tuberculosis, six undernourished subjects (body mass index < 18.5 kg/m2) and seven control subjects from an Indian population. Fasting subjects were infused with l-[1-13C] leucine (2.3 μmol · h−1 · kg−1) for 8 h, 4 h fasted then 4 h fed. Leucine kinetics were derived from 13C-enrichment of leucine and α-ketoisocaproic acid in plasma and CO2 in breath. 3. Undernourished subjects, but not tuberculosis subjects, had higher rates of whole body protein turnover per unit lean body mass than controls [163.1 ± 9.4 and 148.6 ± 14.6 μmol compared with 142.8 ± 14.7 μmol leucine/h per kg, based on α-ketoisocaproic acid enrichment (P = 0.039)]. 4. In response to feeding, protein oxidation increased in all groups. Tuberculosis subjects had the highest fed rates of oxidation (47.0 ± 10.5 compared with 37.1 ± 5.4 μmol · h−1 · kg−1 in controls), resulting in a less positive net protein balance in the fed phase (controls, 39.7 ± 6.2; undernourished subjects, 29.2 ± 10.6; tuberculosis subjects, 24.5 ± 93; P = 0.010). Thus fed-phase tuberculosis subjects oxidized a greater proportion of leucine flux (33.2%) than either of the other groups (controls, 24.0%; undernourished subjects, 24.0%; P = 0.017). 5. Tuberculosis did not increase fasting whole body protein turnover but impaired the anabolic response to feeding compared with control and undernourished subjects. Such ‘anabolic block’ may contribute to wasting in tuberculosis and may represent the mechanism by which some inflammatory states remain refractory to nutrition support.

Chloroquine reduces whole body proteolysis in humans

1994 ◽  
Vol 267 (1) ◽  
pp. E183-E186 ◽  
Author(s):  
P. De Feo ◽  
E. Volpi ◽  
P. Lucidi ◽  
G. Cruciani ◽  
F. Santeusanio ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Plasma Concentrations ◽  
Whole Body ◽  
Body Protein ◽  
Leucine Kinetics ◽  
Lysosomal Proteolysis ◽  
Therapeutic Doses

The antimalaric drug chloroquine is a well known inhibitor of lysosomal proteolysis in vitro. The present study tests the hypothesis that therapeutic doses of the drug decrease proteolysis also in vivo in humans. Leucine kinetics were determined in 20 healthy volunteers given 12 and 1.5 h before the studies 250 and 500 mg, respectively, of chloroquine phosphate (n = 10) or similar tablets of placebo (n = 10). Chloroquine reduced the rates of leucine appearance, a measure of whole body proteolysis, from 2.45 +/- 0.08 to 2.19 +/- 0.08 mumol.kg-1.min-1 (P = 0.038) and those of nonoxidative leucine disposal, an estimate of whole body protein synthesis, from 2.16 +/- 0.08 to 1.95 +/- 0.06 mumol.kg-1.min-1 (P = 0.050). The drug resulted also in a marginally significant (P = 0.051) decrement in the plasma concentrations of glucose. The effects of chloroquine on protein turnover might be potentially useful in counteracting protein wasting complicating several catabolic diseases, whereas those on glucose metabolism can explain the sporadic occurrence of severe hypoglycemic episodes in malaria patients chronically treated with this drug.

Sign in / Sign up

Export Citation Format

Share Document