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Li G, Li Z, Liu J. Amino acids regulating skeletal muscle metabolism: mechanisms of action, physical training dosage recommendations and adverse effects. Nutr Metab (Lond) 2024; 21:41. [PMID: 38956658 PMCID: PMC11220999 DOI: 10.1186/s12986-024-00820-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 06/24/2024] [Indexed: 07/04/2024] Open
Abstract
Maintaining skeletal muscle mass is important for improving muscle strength and function. Hence, maximizing lean body mass (LBM) is the primary goal for both elite athletes and fitness enthusiasts. The use of amino acids as dietary supplements is widespread among athletes and physically active individuals. Extensive literature analysis reveals that branched-chain amino acids (BCAA), creatine, glutamine and β-alanine may be beneficial in regulating skeletal muscle metabolism, enhancing LBM and mitigating exercise-induced muscle damage. This review details the mechanisms of these amino acids, offering insights into their efficacy as supplements. Recommended dosage and potential side effects are then outlined to aid athletes in making informed choices and safeguard their health. Lastly, limitations within the current literature are addressed, highlighting opportunities for future research.
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Affiliation(s)
- Guangqi Li
- School of Physical Education, Northeast Normal university, No. 5268, Renmin Street, Changchun city, Jilin province, 130024, People's Republic of China
| | - Zhaojun Li
- Gaomi Municipal Center for Disease Control and Prevention, Gaomi city, Shandong, People's Republic of China
| | - Junyi Liu
- School of Physical Education, Northeast Normal university, No. 5268, Renmin Street, Changchun city, Jilin province, 130024, People's Republic of China.
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2
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Internal standard metabolites for estimating origin blood volume of bloodstains. Forensic Sci Int 2023; 342:111533. [PMID: 36516660 DOI: 10.1016/j.forsciint.2022.111533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 11/24/2022] [Indexed: 11/28/2022]
Abstract
The volume of blood leaked from blood vessels may change due to evaporation of water under the natural influence of the external environment. Bloodstains and dried blood spots (DBS), which describes blood dried in the external environment, are similar in their production and their metabolite quantification profiles. In both bloodstain metabolite analysis in the forensic science field and DBS metabolite analysis in the clinical field, it is important to determine the volume of the origin blood as this affects metabolite quantification results. Therefore, the purpose of this study is to discover the internal standard metabolites that have quantitatively proportional relationships with origin blood volume and maintain constant concentrations even as the age of the bloodstain increases. As a result, the concentrations of L-isoleucine and L-phenylalanine increased in proportion to the origin blood volume of the bloodstain. The differences in concentration of L-isoleucine were significant in all volume comparisons except in the comparison between 65 μL and 85 μL. The differences in concentration of L-phenylalanine were significant in all volume comparisons except between 65 μL and 45 μL and between 65 μL and 85 μL. In addition, it was confirmed that both metabolites tended to maintain constant concentrations without being affected by bloodstain age as the volume became smaller. These internal standard metabolites can be used for estimating the origin blood volume of bloodstains during metabolite analysis of bloodstains and DBS and could provide a volume criterion for standardization when comparing metabolite quantification between samples.
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Abstract
The aim of the article is to examine side effects of increased dietary intake of amino acids, which are commonly used as a dietary supplement. In addition to toxicity, mutagenicity and carcinogenicity, attention is focused on renal and gastrointestinal tract functions, ammonia production, and consequences of a competition with other amino acids for a carrier at the cell membranes and enzymes responsible for their degradation. In alphabetic order are examined arginine, β-alanine, branched-chain amino acids, carnosine, citrulline, creatine, glutamine, histidine, β-hydroxy-β-methylbutyrate, leucine, and tryptophan. In the article is shown that enhanced intake of most amino acid supplements may not be risk-free and can cause a number of detrimental side effects. Further research is necessary to elucidate effects of high doses and long-term consumption of amino acid supplements on immune system, brain function, muscle protein balance, synthesis of toxic metabolites, and tumor growth and examine their suitability under certain circumstances. These include elderly, childhood, pregnancy, nursing a baby, and medical condition, such as diabetes and liver disease. Studies are also needed to examine adaptive response to a long-term intake of any substance and consequences of discontinuation of supplementation.
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Affiliation(s)
- M HOLEČEK
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, Hradec Králové, Czech Republic
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4
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Ikonen JN, Joro R, Uusitalo AL, Kyröläinen H, Kovanen V, Atalay M, Tanskanen-Tervo MM. Effects of military training on plasma amino acid concentrations and their associations with overreaching. Exp Biol Med (Maywood) 2020; 245:1029-1038. [PMID: 32363923 DOI: 10.1177/1535370220923130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
IMPACT STATEMENT The diagnosis of overtraining syndrome and overreaching poses a great challenge. Military training aims at improving the physical performance of the conscripts, but an excessive training load could also lead to overreaching. This study of Finnish conscripts provides new insights into the pathophysiology of overreaching and overtraining through amino acids concentrations. In addition to confirming the possible use of plasma glutamine/glutamate concentration to indicate and predict overreaching, we made a novel finding, i.e. low alanine and arginine concentrations might have a role in performance decrement and fatigue related to overreaching. Moreover, this study is the first to show the possible association between amino acids with putative neuronal properties and overreaching. Thus, the present findings might help to detect and prevent overreaching and offer a reliable diagnostic approach. In order to avoid overreaching, military training should be planned more periodically and individually, especially during the first four weeks of military service.
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Affiliation(s)
- Jenni N Ikonen
- Institute of Biomedicine, University of Eastern Finland, Kuopio 70211, Finland
| | - Raimo Joro
- Institute of Biomedicine, University of Eastern Finland, Kuopio 70211, Finland
| | - Arja Lt Uusitalo
- Department of Sports and Exercise Medicine, Clinicum, University of Helsinki, Helsinki 00530, Finland.,Clinic for Sports and Exercise Medicine, Foundation for Sports and Exercise Medicine, Helsinki 00530, Finland
| | - Heikki Kyröläinen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä 40014, Finland
| | - Vuokko Kovanen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä 40014, Finland
| | - Mustafa Atalay
- Institute of Biomedicine, University of Eastern Finland, Kuopio 70211, Finland
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5
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Greenham G, Buckley JD, Garrett J, Eston R, Norton K. Biomarkers of Physiological Responses to Periods of Intensified, Non-Resistance-Based Exercise Training in Well-Trained Male Athletes: A Systematic Review and Meta-Analysis. Sports Med 2019; 48:2517-2548. [PMID: 30141022 DOI: 10.1007/s40279-018-0969-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Intensified training is important for inducing adaptations to improve athletic performance, but detrimental performance effects can occur if prescribed inappropriately. Monitoring biomarker responses to training may inform changes in training load to optimize performance. OBJECTIVE This systematic review and meta-analysis aimed to identify biomarkers associated with altered exercise performance following intensified training. METHODS Embase, MEDLINE, CINAHL, Scopus and SPORTDiscus were searched up until September 2017. Included articles were peer reviewed and reported on biomarkers collected at rest in well-trained male athletes before and after periods of intensified training. RESULTS The full text of 161 articles was reviewed, with 59 included (708 participants) and 42 (550 participants) meta-analysed. In total, 118 biomarkers were evaluated, with most being cellular communication and immunity markers (n = 54). Studies most frequently measured cortisol (n = 34), creatine kinase (n = 25) and testosterone (n = 20). Many studies reported decreased immune cell counts following intensified training, irrespective of performance. Moreover, reduced performance was associated with a decrease in neutrophils (d = - 0.57; 95% confidence interval (CI) - 1.07 to - 0.07) and glutamine (d = - 0.37; 95% CI - 0.43 to - 0.31) and an increase in urea concentration (d = 0.80; 95% CI 0.30 to 1.30). In contrast, increased performance was associated with an increased testosterone:cortisol ratio (d = 0.89; 95% CI 0.54 to 1.24). All remaining biomarkers showed no consistent patterns of change with performance. CONCLUSIONS Many biomarkers were altered with intensified training but not in a manner related to changes in exercise performance. Neutrophils, glutamine, urea and the testosterone:cortisol ratio exhibited some evidence of directional changes that corresponded with performance changes therefore indicating potential to track performance. Additional investigations of the potential for these markers to track altered performance are warranted.
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Affiliation(s)
- Grace Greenham
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research and School of Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia. .,Adelaide Football Club, 105 West Lakes Boulevard, West Lakes, Adelaide, SA, 2021, Australia.
| | - Jonathan D Buckley
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research and School of Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - Joel Garrett
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research and School of Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia.,Port Adelaide Football Club, PO Box 379, Port Adelaide, 5015, SA, Australia
| | - Roger Eston
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research and School of Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - Kevin Norton
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research and School of Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
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Zafeiridis A, Chatziioannou AC, Sarivasiliou H, Kyparos A, Nikolaidis MG, Vrabas IS, Pechlivanis A, Zoumpoulakis P, Baskakis C, Dipla K, Theodoridis GA. Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative 1H NMR Metabonomic Study. J Proteome Res 2016; 15:4452-4463. [DOI: 10.1021/acs.jproteome.6b00545] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Andreas Zafeiridis
- Exercise
Physiology and Biochemistry Laboratory, Department of Physical Education
and Sport Sciences at Serres, Aristotle University of Thessaloniki, Serres 62121, Greece
| | | | - Haralambos Sarivasiliou
- Exercise
Physiology and Biochemistry Laboratory, Department of Physical Education
and Sport Sciences at Serres, Aristotle University of Thessaloniki, Serres 62121, Greece
| | - Antonios Kyparos
- Exercise
Physiology and Biochemistry Laboratory, Department of Physical Education
and Sport Sciences at Serres, Aristotle University of Thessaloniki, Serres 62121, Greece
| | - Michalis G. Nikolaidis
- Exercise
Physiology and Biochemistry Laboratory, Department of Physical Education
and Sport Sciences at Serres, Aristotle University of Thessaloniki, Serres 62121, Greece
| | - Ioannis S. Vrabas
- Exercise
Physiology and Biochemistry Laboratory, Department of Physical Education
and Sport Sciences at Serres, Aristotle University of Thessaloniki, Serres 62121, Greece
| | - Alexandros Pechlivanis
- Biomolecular
Medicine, Division of Computational and Systems Medicine, Department
of Surgery and Cancer, Faculty of Medicine, Imperial College London, SW7 2AZ London, United Kingdom
| | - Panagiotis Zoumpoulakis
- Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens, 11635 Greece
| | - Constantinos Baskakis
- Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens, 11635 Greece
| | - Konstantina Dipla
- Exercise
Physiology and Biochemistry Laboratory, Department of Physical Education
and Sport Sciences at Serres, Aristotle University of Thessaloniki, Serres 62121, Greece
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7
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Rodríguez-Gutiérrez R, Lavalle-González FJ, Martínez-Garza LE, Landeros-Olvera E, López-Alvarenga JC, Torres-Sepúlveda MR, González-González JG, Mancillas-Adame LG, Salazar-Gonzalez B, Villarreal-Pérez JZ. Impact of an exercise program on acylcarnitines in obesity: a prospective controlled study. J Int Soc Sports Nutr 2012; 9:22. [PMID: 22574901 PMCID: PMC3428650 DOI: 10.1186/1550-2783-9-22] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 05/10/2012] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Acylcarnitine (AC) transport dysfunction into the mitochondrial matrix is one of the pathophysiological mechanisms of type 2 diabetes mellitus (DM). The effect of an aerobic exercise (AE) program on this condition in obese subjects without DM is unclear. METHODS A prospective, randomized, longitudinal, interventional study in a University Research Center involved a 10-week AE program in 32 women without DM and a body mass index (BMI) greater than 27 kg/m2. (Cases n = 17; Controls n = 15). The primary objective was to evaluate the influence of a controlled AE program on beta-oxidation according to modifications in short, medium, and long-chain ACs. Secondary objectives were to define the behavior of amino acids, and the correlation between these modifications with metabolic and anthropometric markers. RESULTS The proportion of dropouts was 17% and 6% in controls and cases, respectively. In cases there was a significant reduction in total carnitine (30.40 [95% CI 28.2 to 35.6]) vs. (29.4 [CI 95% 25.1 to 31.7]) p = 0.0008 and long-chain AC C14 (0.06 [95% CI 0.05 to 0.08]) vs. (0.05 [95% CI 0.05 to 0.09]) p = 0.005 and in C18 (0.31 [95% CI 0.27 to 0.45]) vs. (0.28 [95% CI 0.22 to 0.32]) p = 0.03. Free fatty acid levels remained without change during the study in both groups. CONCLUSION In conclusion, a controlled 10-week AE program improved beta-oxidation by reducing long-chain ACs. This finding highlights the importance that AE might have in avoiding or reverting lipotoxicity, and in consequence, improving insulin sensitivity and pancreatic beta cell functional reserve.
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Affiliation(s)
- René Rodríguez-Gutiérrez
- Endocrinology Division, Internal Medicine Department, “Dr. José E. González”, University Hospital and Medical School of the Universidad Autónoma de Nuevo León, Ave. Madero y Ave. Gonzalitos s/n, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
| | - Fernando J Lavalle-González
- Endocrinology Division, Internal Medicine Department, “Dr. José E. González”, University Hospital and Medical School of the Universidad Autónoma de Nuevo León, Ave. Madero y Ave. Gonzalitos s/n, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
- Servicio de Endocrinología, Hospital Universitario Dr. José E. Gonzalez, Ave. Madero y Gonzalitos s/n, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
| | - Laura E Martínez-Garza
- Genetics Department, Medical School of the Universidad Autónoma de Nuevo León, Ave. Madero y Dr. Eduardo Aguirre Pequeño s/n, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
| | - Erick Landeros-Olvera
- Cardiovascular Exercise Laboratory, Nursing School of the Benemérita Universidad Autónoma de Puebla, 4 sur 104, Centro Histórico, Puebla, 72000, Mexico
| | - Juan C López-Alvarenga
- Investigation Department of the Hospital General de Mexico, O.D, Dr. Balmis No.148, Col. Doctores, Delegación, Cuauhtémoc, 06726, Mexico
| | - Maria R Torres-Sepúlveda
- Genetics Department, Medical School of the Universidad Autónoma de Nuevo León, Ave. Madero y Dr. Eduardo Aguirre Pequeño s/n, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
| | - Jose G González-González
- Endocrinology Division, Internal Medicine Department, “Dr. José E. González”, University Hospital and Medical School of the Universidad Autónoma de Nuevo León, Ave. Madero y Ave. Gonzalitos s/n, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
| | - Leonardo G Mancillas-Adame
- Endocrinology Division, Internal Medicine Department, “Dr. José E. González”, University Hospital and Medical School of the Universidad Autónoma de Nuevo León, Ave. Madero y Ave. Gonzalitos s/n, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
| | - Bertha Salazar-Gonzalez
- Investigation Department, Nursing School, Universidad Autónoma de Nuevo León, Av. Gonzalitos 1500 Norte, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
| | - Jesus Z Villarreal-Pérez
- Endocrinology Division, Internal Medicine Department, “Dr. José E. González”, University Hospital and Medical School of the Universidad Autónoma de Nuevo León, Ave. Madero y Ave. Gonzalitos s/n, Colonia Mitras Centro, Monterrey, Nuevo León, 64460, Mexico
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8
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Holecek M. Adverse effects of chronic intake of glutamine-supplemented diet on amino acid concentrations and protein metabolism in rat: Effect of short-term starvation. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.eclnm.2011.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Abstract
In situations of stress, such as clinical trauma, starvation or prolonged, strenuous exercise, the concentration of glutamine in the blood is decreased, often substantially. In endurance athletes this decrease occurs concomitantly with relatively transient immunodepression. Glutamine is used as a fuel by some cells of the immune system. Provision of glutamine or a glutamine precursor, such as branched chain amino acids, has been seen to have a beneficial effect on gut function, on morbidity and mortality, and on some aspects of immune cell function in clinical studies. It has also been seen to decrease the self-reported incidence of illness in endurance athletes. So far, there is no firm evidence as to precisely which aspect of the immune system is affected by glutamine feeding during the transient immunodepression that occurs after prolonged, strenuous exercise. However, there is increasing evidence that neutrophils may be implicated. Other aspects of glutamine and glutamine supplementation are also addressed.
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Affiliation(s)
- Linda Castell
- Nuffield Department of Anaesthetics, University of Oxford, England.
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10
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Castell LM. Can glutamine modify the apparent immunodepression observed after prolonged, exhaustive exercise? Nutrition 2002; 18:371-5. [PMID: 11985938 DOI: 10.1016/s0899-9007(02)00754-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glutamine is an important fuel for some cells of the immune system. In situations of stress, such as clinical trauma, starvation, or prolonged, strenuous exercise, the concentration of glutamine in blood is decreased, often substantially. In endurance athletes this decrease occurs concomitantly with relatively transient immunodepression. Provision of glutamine or a glutamine precursor has been found to decrease the incidence of illness in endurance athletes. To date, it has not been established precisely which aspect of the immune system is affected by glutamine feeding during the transient immunodepression that occurs after prolonged, strenuous exercise. However, there is increasing evidence that neutrophils may be implicated.
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Affiliation(s)
- Linda M Castell
- University Department of Biochemistry, Oxford University, Oxford, United Kingdom.
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11
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MacLaren DP, Nevill AM, Thake CD, Campbell IT, Cheetham E, Keegan MA, Lane C, Roberts NB. Human erythrocyte and plasma amino acid concentrations during exercise. Med Sci Sports Exerc 2000; 32:1244-9. [PMID: 10912889 DOI: 10.1097/00005768-200007000-00010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE This investigation examined the effects of exercise and maltodextrin (Md) or placebo (Pl) ingestion on plasma and erythrocyte concentrations of amino acids. METHODS The erythrocyte and plasma concentrations of 17 amino acids, as well as plasma glucose and insulin, were analyzed in eight healthy trained male subjects before, during, and 25 min after 90-min cycle ergometer exercise at 65% peak oxygen uptake. The two treatments involved ingestion of orange-flavored water (Pl) or orange-flavored 10% maltodextrin solution (Md). RESULTS Two-way ANOVA revealed 1) that plasma concentrations of alanine and tyrosine changed significantly during the treatments, 2) that the plasma concentrations were significantly different between treatments for glycine and threonine, 3) that all erythrocyte concentrations increased significantly throughout the treatments except for arginine and tyrosine, and 4) that there were no significant differences in erythrocyte concentrations between the treatments. Three-way ANOVA highlighted the significant differences in the time responses between plasma and erythrocyte concentrations; the changes in erythrocyte levels from rest being significantly different from plasma for all amino acids except aspartic acid, glycine, and ornithine. Plasma glucose concentrations became elevated and remained above rest values in Md but fell below rest values in Pl: the differences in concentration between treatments were significant. Correspondingly, plasma insulin was significantly higher in Md during exercise. CONCLUSION These results highlight that far from being slow in the uptake of amino acids, the erythrocyte in fact sequesters amino acids at an appreciable rate during exercise without a corresponding elevation in the plasma amino acids. For a greater understanding of amino acid changes during exercise, the analysis of both plasma and erythrocytes is recommended.
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Affiliation(s)
- D P MacLaren
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, United Kingdom.
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12
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Conlay LA, Wurtman RJ, Lopez G-Coviella I, Blusztajn JK, Vacanti CA, Logue M, During M, Caballero B, Maher TJ, Evoniuk G. Effects of running the Boston marathon on plasma concentrations of large neutral amino acids. J Neural Transm (Vienna) 1989; 76:65-71. [PMID: 2708978 DOI: 10.1007/bf01244992] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Plasma large neutral amino acid concentrations were measured in thirty-seven subjects before and after completing the Boston Marathon. Concentrations of tyrosine, phenylalanine, and methionine increased, as did their "plasma ratios" (i.e., the ratio of each amino acid's concentration to the summed plasma concentrations of the other large neutral amino acids which compete with it for brain uptake). No changes were noted in the plasma concentrations of tryptophan, leucine, isoleucine, nor valine; however, the "plasma ratios" of acid patterns may influence neurotransmitter synthesis.
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Affiliation(s)
- L A Conlay
- Laboratory of Neuroendocrine Regulation, Massachusetts Institute of Technology, Cambridge
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13
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Gleeson M, Maughan RJ. A simple enzymatic fluorimetric method for the determination of branched-chain L-amino acids in microlitre volumes of plasma. Clin Chim Acta 1987; 166:163-9. [PMID: 3621597 DOI: 10.1016/0009-8981(87)90418-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Existing methods for the estimation of the branched-chain amino acids (BCAA) normally require sophisticated, expensive instrumentation. An alternative is an enzymatic spectrophotometric method but this requires relatively large volumes of blood and is rather time-consuming. A simple enzymatic fluorimetric method for the measurement of the BCAA in microliter samples of plasma is described here. The method is based on the oxidative deamination of L-leucine, L-isoleucine and L-valine by leucine dehydrogenase from Bacillus species. The NADH which is formed in stoichiometric quantities is estimated fluorimetrically. In the presence of the ketone-trapping agent hydrazine the reaction goes to completion in an alkaline incubation medium at 37 degrees C. By this method the combined BCAA can be measured routinely in 20 microliter sample of plasma. The test exhibits acceptable precision and reproducibility.
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14
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Lemon PW, Benevenga NJ, Mullin JP, Nagle FJ. Effect of daily exercise and food intake on leucine oxidation. BIOCHEMICAL MEDICINE 1985; 33:67-76. [PMID: 3922359 DOI: 10.1016/0006-2944(85)90128-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Oxidation of the branched-chain amino acid leucine was studied in 22 male Sprague-Dawley rats (70-90 g) over 3 days following the ingestion on Day 1 of a mixed diet containing a tracer dose (10 muCi) of L-[1-14C]Leu. One group (E) completed 1 hr exercise at 80% VO2 max immediately after a 2-hr feeding period on all 3 days, while a second group served as a control. Rats from group E were sacrificed immediately after the 2 hr feeding on Day 1, following exercise on Days 1 and 3, and at the end of Day 3. The following were determined: (1) continuous 14CO2 production, (2) radioactivity remaining in the gastrointestinal tract, and (3) distribution of free vs protein bound 14C in muscle and liver. The results indicated that (1) 14CO2 production increased during exercise on all 3 days (P less than 0.01), (2) 14CO2 production also increased (P less than 0.05) following food intake (unlabeled diet), (3) 14CO2 production due to exercise was greater than that due to food intake (P less than 0.05), (4) absolute 14CO2 production decreased dramatically by 15 hr of Day 1 (P less than 0.01) with little change thereafter (except with exercise and food intake on Days 2 and 3), (5) greater than 98% of the labeled diet was absorbed from the GIT 51 hr postingestion, and (6) 14C in the free pool of muscle and liver could account for less than 15% of the total 14CO2 production. These results suggest that protein bound 14C in addition to free 14C may be responsible for a significant proportion of the observed increased 14CO2 production during exercise.
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15
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Refsum HE, Gjessing LR, Strømme SB. Changes in plasma amino acid distribution and urine amino acids excretion during prolonged heavy exercise. Scand J Clin Lab Invest 1979; 39:407-13. [PMID: 523987 DOI: 10.3109/00365517909106125] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Venous plasma and urine amino acids and urea were measured in ten well-trained men, aged 23--45 years, in connection with a 70 km cross-country ski race, lasting 4.39--6.04 h, leading to slight dehydration. The estimated urea production rate during the race was of the order 7.6 mumol/min, kg b.wt, i.e. twice the rate for such men on ordinary protein intake, during ordinary activity, thus suggesting increased protein catabolism. The race led to a fall of the total plasma amino acid concentration to about 60% of the pre-race level. In particular, the branched chain amino acids (valine, iso-leucine, leucine) and alanine were markedly reduced, whereas the S-containing amino acids (taurine, cystine, methionine) and the aromatic (phenylalanine, tyrosine, trytophan, histidine) and glutamine/glutamate were increased, unchanged or only moderately reduced. It is concluded that prolonged heavy exercise is accompanied by increased protein catabolism and changes in the plasma amino acid concentrations similar to those observed during prolonged starvation, but differing from those seen at heavy exercise of less than 2 h duration or prolonged exercise of moderate intensity.
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16
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Berg A, Gerok W, Keul J. Serum alanine assay with an enzymic micromethod (L-alanine dehydrogenase). Clin Chim Acta 1978; 86:95-100. [PMID: 26488 DOI: 10.1016/0009-8981(78)90463-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
L-Alanine was measured by an enzymic micromethod in serum after treatment with perchloric acid, as well as after ultrafiltration through collodium membrane filters. Serum L-alanine was also determined by an automated column chromatographic technique. Using the enzymic method, spuriously increased L-alanine levels could be obtained due to the absorbent reaction between hydrazine and NAD-containing reagents. It could be shown that this absorbent reaction depends on the pH value of the test solution. In contrast to supernatant diluted by perchloric acid, ultrafiltrates gave L-alanine data equivalent to those by column chromatography, since conditions of reaction time and pH value could be kept identical for blank, standard and ultrafiltrate solutions.
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17
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Abstract
The immediate and delayed influence of exercise of variable type, duration and intensity on the serum gamma-glutamyl transpeptidase activity (gamma-GT) has been examined in athletes and untrained persons. The possible effects of exercise-induced changes in other parameters (plasma free glutamate, serum triglyceride, haemoconcentration) on the measured postexercise serum gamma-GT have been discussed, partly on the basis of our own experimental data. It appears that neither exercise itself, nor any one of the above mentioned factors (excepting a slight, transient effect of haemoconcentration after brief, intensive exertion) have noticeable influence on serum gamma-GT. Determinations of this enzyme for diagnostic purposes are therefore likely to be used without regard to acute and chronic exercise history in man.
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