Regional muscle and adipose tissue amino acid  metabolism in lean and obese women

The effect of obesity on regional skeletal muscle and adipose tissue amino acid metabolism is not known. We evaluated systemic and regional (forearm and abdominal subcutaneous adipose tissue) amino acid metabolism, by use of a combination of stable isotope tracer and arteriovenous balance methods, in five lean women [body mass index (BMI) <25 kg/m2] and five women with abdominal obesity (BMI 35.0–39.9 kg/m2; waist circumference >100 cm) who were matched on fat-free mass (FFM). All subjects were studied at 22 h of fasting to ensure that the subjects were in net protein breakdown during this early phase of starvation. Leucine rate of appearance in plasma (an index of whole body proteolysis), expressed per unit of FFM, was not significantly different between lean and obese groups (2.05 ± 0.18 and 2.34 ± 0.04 μmol · kg FFM−1 · min−1, respectively). However, the rate of leucine release from forearm and adipose tissues in obese women (24.0 ± 4.8 and 16.6 ± 6.5 nmol · 100 g−1 · min−1, respectively) was lower than in lean women (66.8 ± 10.6 and 38.6 ± 7.0 nmol · 100 g−1 · min−1, respectively; P < 0.05). Approximately 5–10% of total whole body leucine release into plasma was derived from adipose tissue in lean and obese women. The results of this study demonstrate that the rate of release of amino acids per unit of forearm and adipose tissue at 22 h of fasting is lower in women with abdominal obesity than in lean women, which may help obese women decrease body protein losses during fasting. In addition, adipose tissue is a quantitatively important site for proteolysis in both lean and obese subjects.

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Interactive effects of aging and aerobic capacity on energy metabolism–related metabolites of serum, skeletal muscle, and white adipose tissue

GeroScience ◽

10.1007/s11357-021-00387-1 ◽

2021 ◽

Author(s):

Haihui Zhuang ◽

Sira Karvinen ◽

Timo Törmäkangas ◽

Xiaobo Zhang ◽

Xiaowei Ojanen ◽

...

Keyword(s):

Adipose Tissue ◽

Amino Acid ◽

White Adipose Tissue ◽

Aerobic Capacity ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Disease Risk ◽

Whole Body ◽

Whole Body Metabolism

AbstractAerobic capacity is a strong predictor of longevity. With aging, aerobic capacity decreases concomitantly with changes in whole body metabolism leading to increased disease risk. To address the role of aerobic capacity, aging, and their interaction on metabolism, we utilized rat models selectively bred for low and high intrinsic aerobic capacity (LCRs/HCRs) and compared the metabolomics of serum, muscle, and white adipose tissue (WAT) at two time points: Young rats were sacrificed at 9 months of age, and old rats were sacrificed at 21 months of age. Targeted and semi-quantitative metabolomics analysis was performed on the ultra-pressure liquid chromatography tandem mass spectrometry (UPLC-MS) platform. The effects of aerobic capacity, aging, and their interaction were studied via regression analysis. Our results showed that high aerobic capacity is associated with an accumulation of isovalerylcarnitine in muscle and serum at rest, which is likely due to more efficient leucine catabolism in muscle. With aging, several amino acids were downregulated in muscle, indicating more efficient amino acid metabolism, whereas in WAT less efficient amino acid metabolism and decreased mitochondrial β-oxidation were observed. Our results further revealed that high aerobic capacity and aging interactively affect lipid metabolism in muscle and WAT, possibly combating unfavorable aging-related changes in whole body metabolism. Our results highlight the significant role of WAT metabolism for healthy aging.

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Impact of habituated dietary protein intake on fasting and postprandial whole-body protein turnover and splanchnic amino acid metabolism in elderly men: a randomized, controlled, crossover trial

American Journal of Clinical Nutrition ◽

10.1093/ajcn/nqaa201 ◽

2020 ◽

Vol 112 (6) ◽

pp. 1468-1484 ◽

Cited By ~ 2

Author(s):

Grith Højfeldt ◽

Jacob Bülow ◽

Jakob Agergaard ◽

Ali Asmar ◽

Peter Schjerling ◽

...

Keyword(s):

Amino Acid ◽

Protein Turnover ◽

Protein Intake ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

High Protein ◽

Whole Body ◽

Body Protein ◽

Protein Absorption ◽

Fasted State

ABSTRACT Background Efficacy of protein absorption and subsequent amino acid utilization may be reduced in the elderly. Higher protein intakes have been suggested to counteract this. Objectives We aimed to elucidate how habituated amounts of protein intake affect the fasted state of, and the stimulatory effect of a protein-rich meal on, protein absorption, whole-body protein turnover, and splanchnic amino acid metabolism. Methods Twelve men (65–70 y) were included in a double-blinded crossover intervention study, consisting of a 20-d habituation period to a protein intake at the RDA or a high amount [1.1 g · kg lean body mass (LBM)−1 · d−1 or >2.1 g · kg LBM−1 · d−1, respectively], each followed by an experimental trial with a primed, constant infusion of D8-phenylalanine and D2-tyrosine. Arterial and hepatic venous blood samples were obtained after an overnight fast and repeatedly 4 h after a standardized meal including intrinsically labeled whey protein concentrate and calcium-caseinate proteins. Blood was analyzed for amino acid concentrations and phenylalanine and tyrosine tracer enrichments from which whole-body and splanchnic amino acid and protein kinetics were calculated. Results High (compared with the recommended amount of) protein intake resulted in a higher fasting whole-body protein turnover with a resultant mean ± SEM 0.03 ± 0.01 μmol · kg LBM−1 · min−1 lower net balance (P < 0.05), which was not rescued by the intake of a protein-dense meal. The mean ± SEM plasma protein fractional synthesis rate was 0.13 ± 0.06%/h lower (P < 0.05) after habituation to high protein. Furthermore, higher fasting and postprandial amino acid removal were observed after habituation to high protein, yielding higher urea excretion and increased phenylalanine oxidation rates (P < 0.01). Conclusions Three weeks of habituation to high protein intake (>2.1 g protein · kg LBM−1 · d−1) led to a significantly higher net protein loss in the fasted state. This was not compensated for in the 4-h postprandial period after intake of a meal high in protein. This trial was registered at clinicaltrials.gov as NCT02587156.

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Exercise-Mediated Peripheral Tissue and Whole-Body Amino Acid Metabolism during Intravenous Feeding in Normal Man

Clinical Science ◽

10.1042/cs0770113 ◽

1989 ◽

Vol 77 (1) ◽

pp. 113-120 ◽

Cited By ~ 13

Author(s):

James D. Albert ◽

Dwight E. Matthews ◽

Adrian Legaspi ◽

Kevin J. Tracey ◽

Malayappa Jeevanandam ◽

...

Keyword(s):

Amino Acid ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Submaximal Exercise ◽

Peripheral Tissue ◽

Whole Body ◽

Total Amino Acid ◽

Body Protein ◽

Daily Exercise ◽

Amino Acid Flux

1. The effect of a daily submaximal exercise regimen on whole-body and peripheral tissue amino acid metabolism during weight-stable intravenous feeding (IVF) was evaluated in 11 normal volunteers. Five of the subjects performed 1 h of daily bicycle exercise at 75 W during IVF, while the remaining six subjects received IVF without daily exercise. Body nitrogen balance, leg and forearm plasma amino acid flux and whole-body kinetics were measured before and on day 10 of IVF using a [1-13C]leucine and [15N]glycine tracer. 2. At the end of the IVF period, exercised subjects demonstrated leg uptake of total amino acids (237 ± 103 nmol min−1 100 ml−1 of tissue, mean ± sem) which was significantly (P < 0.05) different than in non-exercised subjects (− 1101 ± 253 nmol min−1 100 ml−1 of tissue). 3. In the non-exercised forearm, a significant (P < 0.05) decrease in total amino acid flux was observed in exercised subjects (− 162 ± 88 nmol min−1 100 ml−1 of tissue) compared with non-exercised subjects (−460 ± 105 nmol min−1 100 ml−1 of tissue) on day 10 of IVF. 4. Efflux of 3-methylhistidine significantly (P < 0.05) decreased from the leg in those subjects who performed daily exercise (−0.29 ± 0.12 nmol min−1 100 ml−1 of tissue) compared with those subjects receiving IVF without daily exercise (− 1.46 ± 0.35 nmol min−1 100 ml−1 of tissue). 5. Although IVF increased whole-body leucine turnover in both exercised and non-exercised subjects, only exercised subjects demonstrated a significant (P < 0.05) increase in leucine oxidation which was proportionate to an increased muscle uptake of leucine. Whole-body protein breakdown, as assessed by [15N]glycine, was significantly (P < 0.05) decreased in exercised subjects compared with non-exercised subjects during IVF. 6. These data demonstrate that daily submaximal exercise produced a systemic as well as limb-specific enhancement of amino acid balance in muscle, providing an anti-catabolic response under conditions of partial immobility induced by hospitalization.

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Whole body protein and amino acid metabolism: relation to protein quality evaluation in human nutrition

Journal of Agricultural and Food Chemistry ◽

10.1021/jf00105a003 ◽

1981 ◽

Vol 29 (3) ◽

pp. 440-447 ◽

Cited By ~ 25

Author(s):

Vernon R. Young ◽

Nevin S. Scrimshaw ◽

Dennis M. Bier

Keyword(s):

Amino Acid ◽

Amino Acid Metabolism ◽

Quality Evaluation ◽

Acid Metabolism ◽

Protein Quality ◽

Human Nutrition ◽

Whole Body ◽

Body Protein

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Amino acid metabolism after intense exercise

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1990.258.2.e249 ◽

1990 ◽

Vol 258 (2) ◽

pp. E249-E255 ◽

Cited By ~ 5

Author(s):

J. T. Devlin ◽

I. Brodsky ◽

A. Scrimgeour ◽

S. Fuller ◽

D. M. Bier

Keyword(s):

Protein Synthesis ◽

Amino Acid ◽

Protein Degradation ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Recovery Period ◽

Whole Body ◽

Protein Breakdown ◽

Body Protein ◽

Leucine Oxidation

We studied postexercise amino acid metabolism, in the whole body and across the forearm. Seven volunteers were infused with L-[alpha-15N]lysine and L-[1-13C]-leucine twice [one time during 3 h after cycle exercise (75% VO2max), and one time in the resting state]. Whole body protein breakdown was estimated from dilution of L-[alpha-15N]lysine and L-[1-13C]ketoisocaproic acid (KIC) enrichments in plasma. Leucine oxidation was calculated from 13CO2 enrichments in expired air. Whole body protein breakdown was not increased above resting levels during the recovery period. Leucine oxidation was decreased after exercise (postexercise 13 +/- 2.3 vs. resting 19 +/- 3.2 mumol.kg-1.h-1; P less than 0.02), while nonoxidative leucine disposal was increased (115 +/- 6.1 vs. 103 +/- 5.6 micrograms.kg-1.min-1; P less than 0.02). After exercise, forearm net lysine balance was unchanged (87 +/- 25 vs. 93 +/- 28 nmol.100 ml-1.min-1), but there were decreases in forearm muscle protein degradation (219 +/- 51 vs. 356 +/- 85 nmol.100 ml-1.min-1; P less than 0.05) and synthesis (132 +/- 41 vs. 255 +/- 69 nmol.100 ml-1.min-1; P less than 0.01). In conclusion, after exercise 1) whole body protein degradation is not increased, 2) leucine disposal is directed away from oxidative and toward nonoxidative pathways, 3) forearm protein synthesis is decreased. Postexercise increases in whole body protein synthesis occur in tissues other than nonexercised muscle.

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Interactive effects of aging and aerobic capacity on energy metabolism-related metabolites of serum, skeletal muscle, and white adipose tissue

10.1101/2020.07.16.207746 ◽

2020 ◽

Author(s):

Haihui Zhuang ◽

Sira Karvinen ◽

Xiaobo Zhang ◽

Xiaowei Ojanen ◽

Timo Törmakangas ◽

...

Keyword(s):

Adipose Tissue ◽

Amino Acid ◽

Energy Metabolism ◽

White Adipose Tissue ◽

Aerobic Capacity ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Interactive Effects ◽

Whole Body ◽

Effects Of Aging

ABSTRACTAerobic capacity is a strong predictor of longevity. With aging, aerobic capacity decreases concomitantly with changes in whole body metabolism leading to increased disease risk. To address the role of aerobic capacity, aging and their interaction on metabolism, we utilized rat models of low and high intrinsic aerobic capacity (LCRs/HCRs) and assessed the metabolomics of serum, muscle, and white adipose tissue (WAT). We compared LCRs and HCRs at two time points: Young rats were sacrificed at 9 months, and old rats were sacrificed at 21 months. Targeted and semi-quantitative metabolomics analysis was performed on ultra-pressure Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS) platform. Interaction of aerobic capacity and aging was studied via regression analysis. Our results showed at young age, metabolites linked to amino acid metabolism differed in serum and muscle with aerobic capacity, whereas no difference were observed in WAT. In aged animals, most prominent changes in metabolites occurred in WAT. Aerobic capacity and aging interactively affected seven metabolites linked to energy metabolism. Our results support previous findings that high aerobic capacity is associated with more efficient amino acid metabolism in muscle. While impaired branched chain amino acids (BCAAs) and fatty acid metabolism in the muscle may associate to the high risk of metabolic disorders and shorter lifespan previously observed in LCRs. The interactive effects of aging and aerobic capacity on energy metabolism-related metabolites were largely driven by HCRs, reflecting the importance of inherited aerobic capacity in the aging process. Our results highlight that dysfunctional mitochondrial β-oxidation in WAT may be one key mechanism related to aging.

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Amino acid metabolism in human subcutaneous adipose tissue in vivo

Clinical Science ◽

10.1042/cs0800471 ◽

1991 ◽

Vol 80 (5) ◽

pp. 471-474 ◽

Cited By ~ 46

Author(s):

K. N. Frayn ◽

K. Khan ◽

S. W. Coppack ◽

M. Elia

Keyword(s):

Adipose Tissue ◽

Amino Acid ◽

Subcutaneous Adipose Tissue ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Whole Body ◽

Tissue Blood Flow ◽

Short Period ◽

Body Production ◽

Subcutaneous Adipose

1. Arteriovenous differences for alanine, glutamate and glutamine were measured across subcutaneous adipose tissue and forearm muscle in normal subjects. 2. After an overnight fast, adipose tissue showed net production of alanine and glutamine and uptake of glutamate in each of 11 subjects. 3. In seven subjects, adipose tissue blood flow was measured and the measurements were continued for 6 h after eating a mixed meal. The pattern of amino acid metabolism across the adipose tissue was remarkably little disturbed after the meal, except for a short period of apparent uptake of alanine as the concentration of that amino acid rose. 4. The pattern of amino acid metabolism across adipose tissue was qualitatively similar to that across the forearm, although it differed quantitatively in that glutamate uptake was more prominent (compared with glutamine release) in the adipose tissue. 5. The rates of alanine and glutamine release observed suggest that adipose tissue may play a substantial role in the whole-body production of these amino acids.

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