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Kamada N, Ikeda A, Makino Y, Matsubara H. Intersubunit communication in glycogen phosphorylase influences substrate recognition at the catalytic sites. Amino Acids 2024; 56:14. [PMID: 38340233 PMCID: PMC10858836 DOI: 10.1007/s00726-023-03362-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 12/18/2023] [Indexed: 02/12/2024]
Abstract
Glycogen phosphorylase (GP) is biologically active as a dimer of identical subunits, each activated by phosphorylation of the serine-14 residue. GP exists in three interconvertible forms, namely GPa (di-phosphorylated form), GPab (mono-phosphorylated form), and GPb (non-phosphorylated form); however, information on GPab remains scarce. Given the prevailing view that the two GP subunits collaboratively determine their catalytic characteristics, it is essential to conduct GPab characterization to gain a comprehensive understanding of glycogenolysis regulation. Thus, in the present study, we prepared rabbit muscle GPab from GPb, using phosphorylase kinase as the catalyst, and identified it using a nonradioactive phosphate-affinity gel electrophoresis method. Compared with the half-half GPa/GPb mixture, the as-prepared GPab showed a unique AMP-binding affinity. To further investigate the intersubunit communication in GP, its catalytic site was probed using pyridylaminated-maltohexaose (a maltooligosaccharide-based substrate comprising the essential dextrin structure for GP; abbreviated as PA-0) and a series of specifically modified PA-0 derivatives (substrate analogs lacking part of the essential dextrin structure). By comparing the initial reaction rates toward the PA-0 derivative (Vderivative) and PA-0 (VPA-0), we demonstrated that the Vderivative/VPA-0 ratio for GPab was significantly different from that for the half-half GPa/GPb mixture. This result indicates that the interaction between the two GP subunits significantly influences substrate recognition at the catalytic sites, thereby providing GPab its unique substrate recognition profile.
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Affiliation(s)
- Nahori Kamada
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Japan
| | - Ayato Ikeda
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Japan
| | - Yasushi Makino
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Japan.
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka, 599-8531, Japan.
| | - Hiroshi Matsubara
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Japan
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka, 599-8531, Japan
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Abbotts KSS, Ewell TR, Bomar MC, Butterklee HM, Bell C. Caffeine Augments the Lactate and Interleukin-6 Response to Moderate-Intensity Exercise. Med Sci Sports Exerc 2023; 55:982-990. [PMID: 36719416 DOI: 10.1249/mss.0000000000003121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
INTRODUCTION The release of interleukin (IL)-6 from contracting skeletal muscle is thought to contribute to some of the health benefits bestowed by exercise. This IL-6 response seems proportional to exercise volume and to lactate production. Unfortunately, high volumes of exercise are not feasible for all people. Caffeine augments the magnitude of increase in circulating IL-6 in response to high-intensity and long-duration exercise. Caffeine also increases circulating concentrations of lactate during exercise. We hypothesized that caffeine, ingested before short-duration, moderate-intensity exercise, would lead to greater circulating concentrations of lactate and IL-6 in a study population comprising both male and female individuals. METHODS Twenty healthy adults (10 men and 10 women age 25 ± 7 yr (mean ± SD)) completed 30 min of moderate-intensity cycle ergometer exercise, at an intensity corresponding to 60% peak oxygen uptake, after ingesting either caffeine (6 mg·kg -1 ) or placebo. Arterialized-venous blood was collected throughout each of the exercise sessions. RESULTS Compared with placebo, caffeine increased circulating concentrations of lactate at the end of exercise (5.12 ± 3.67 vs 6.45 ± 4.40 mmol·L -1 , P < 0.001) and after 30 min of inactive recovery (1.83 ± 1.59 vs 2.32 ± 2.09 mmol·L -1 , P = 0.006). Circulating IL-6 concentrations were greatest after 30 min of inactive recovery ( P < 0.001) and higher with caffeine (2.88 ± 2.05 vs 4.18 ± 2.97, pg·mL -1 , P < 0.001). Secondary analysis indicated sex differences; caffeine increased the IL-6 response to exercise in men ( P = 0.035) but not in women ( P = 0.358). CONCLUSIONS In response to moderate-intensity exercise, caffeine evoked greater circulating lactate concentrations in men and women but only increased the IL-6 response to exercise in men. These novel findings suggest that for men unwilling or unable to perform high-intensity and/or long-duration exercise, caffeine may augment the health benefits of relatively short, moderate-intensity exercise.
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Fenne KT, Clauss M, Schäfer Olstad D, Johansen EI, Jensen J. An Acute Bout of Endurance Exercise Does Not Prevent the Inhibitory Effect of Caffeine on Glucose Tolerance the following Morning. Nutrients 2023; 15:nu15081941. [PMID: 37111160 PMCID: PMC10143402 DOI: 10.3390/nu15081941] [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: 03/17/2023] [Revised: 03/29/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Caffeine reduces glucose tolerance, whereas exercise training improves glucose homeostasis. The aim of the present study was to investigate the effect of caffeine on glucose tolerance the morning after an acute bout of aerobic exercise. Methods: The study had a 2 × 2 factorial design. Oral glucose tolerance tests (OGTT) were performed after overnight fasting with/without caffeine and with/without exercise the evening before. Eight healthy young active males were included (Age 25.5 ± 1.5 years; 83.9 ± 9.0 kg; VO2max: 54.3 ± 7.0 mL·kg-1·min-1). The exercise session consisted of 30 min cycling at 71% of VO2max followed by four 5 min intervals at 84% with 3 min of cycling at 40% of VO2max between intervals. The exercise was performed at 17:00 h. Energy expenditure at each session was ~976 kcal. Lactate increased to ~8 mM during the exercise sessions. Participants arrived at the laboratory the following morning at 7.00 AM after an overnight fast. Resting blood samples were taken before blood pressure and heart rate variability (HRV) were measured. Caffeine (3 mg/kg bodyweight) or placebo (similar taste/flavor) was ingested, and blood samples, blood pressure and HRV were measured after 30 min. Next, the OGTTs were initiated (75 g glucose dissolved in 3 dL water) and blood was sampled. Blood pressure and HRV were measured during the OGTT. Caffeine increased the area under curve (AUC) for glucose independently of whether exercise was done the evening before (p = 0.03; Two-way ANOVA; Interaction: p = 0.835). Caffeine did not significantly increase AUC for C-peptides compared to placebo (p = 0.096), and C-peptide response was not influenced by exercise. The acute bout of exercise did not significantly improve glucose tolerance the following morning. Diastolic blood pressure during the OGTT was slightly higher after intake of caffeine, independent of whether exercise was performed the evening before or not. Neither caffeine nor exercise the evening before significantly influenced HRV. In conclusion, caffeine reduced glucose tolerance independently of whether endurance exercise was performed the evening before. The low dose of caffeine did not influence heart rate variability but increased diastolic blood pressure slightly.
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Affiliation(s)
- Karoline T Fenne
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | - Matthieu Clauss
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | | | - Egil I Johansen
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | - Jørgen Jensen
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
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Nunes B, Santos J, Dionísio R, Dias de Alkimin G. Investigation of potential behavioral and physiological effects of caffeine on D. magna. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:43237-43250. [PMID: 35094280 DOI: 10.1007/s11356-022-18695-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
With the ever-increasing consumption of pharmaceutical compounds, their presence in the environment is now an undisputable reality. The majority of these compounds are released into the wild after their therapeutic use, as biotransformation products or in their original form. The presence of this class of compounds in the environment, due to their biological properties, can exert effects on non-target organisms, with adverse consequences. In addition, some bioactive substances, such as stimulants of the central nervous system, are also used by humans as part of their diet. The adverse consequences posed by such chemicals may be permanent or transient, if the exposure to xenobiotics is halted; it is thus of the paramount importance to study effects that result from long-term exposure to toxicants, but also the recovery of organisms previously exposed to such substances, especially if such chemicals may cause some type of addiction. Caffeine (1,3,7-trimethylxanthine) is a naturally occurring alkaloid found in many plants, being one of the most common stimulant/pharmaceutical compounds found in the environment. In addition, it is addictive, and strongly consumed by humans, a factor that contributes also for its continuous presence in the aquatic environment. The aim of this study was to evaluate the effects of environmentally relevant concentrations (0.08; 0.4; 2; 10; and 50 μg/L) of caffeine on behavior and physiological parameters (that are proxies of metabolic traits, such as oxygen uptake and glycogen content), in individuals of the freshwater crustacean species Daphnia magna, of distinct ages, and with or without a recovery period in the absence of caffeine. Regarding behavior, the results indicated that caffeine exposure altered the moved distance of the test organisms, but not according to a coherent pattern; low concentrations of caffeine reduced the movement of exposed daphnids, while higher levels did not have any measurable effect on this parameter. In addition, it was possible to identify subtle withdrawal effects (animals exposed to caffeine during 21 days and kept in uncontaminated media for 2 days). Regarding the other two studied parameters, caffeine exposure did not result in any significant modification in oxygen uptake and glycogen stores/reserves of the test organisms, in animals continuously exposed, or in those subjected to a recovery period, suggesting that despite a behavioral stimulatory effect, this was not followed by any metabolic change, and no addictive effect was possible to infer. The results showed that the presence of caffeine in environmental concentrations can induce mild behavioral effects at low, albeit realistic levels, but not capable of establishing clear biochemical changes.
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Affiliation(s)
- Bruno Nunes
- Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
- Centro de Estudos Do Ambiente E Do Mar (CESAM), Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
| | - João Santos
- Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Ricardo Dionísio
- Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Gilberto Dias de Alkimin
- Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
- Centro de Estudos Do Ambiente E Do Mar (CESAM), Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
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Yang L, Yu X, Zhang Y, Liu N, Xue X, Fu J. Encephalopathy in Preterm Infants: Advances in Neuroprotection With Caffeine. Front Pediatr 2021; 9:724161. [PMID: 34660486 PMCID: PMC8517339 DOI: 10.3389/fped.2021.724161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 09/03/2021] [Indexed: 12/20/2022] Open
Abstract
With the improvement in neonatal rescue technology, the survival rate of critically ill preterm infants has substantially increased; however, the incidence of brain injury and sequelae in surviving preterm infants has concomitantly increased. Although the etiology and pathogenesis of preterm brain injury, and its prevention and treatment have been investigated in recent years, powerful and effective neuroprotective strategies are lacking. Caffeine is an emerging neuroprotective drug, and its benefits have been widely recognized; however, its effects depend on the dose of caffeine administered, the neurodevelopmental stage at the time of administration, and the duration of exposure. The main mechanisms of caffeine involve adenosine receptor antagonism, phosphodiesterase inhibition, calcium ion activation, and γ-aminobutyric acid receptor antagonism. Studies have shown that there are both direct and indirect beneficial effects of caffeine on the immature brain. Accordingly, this article briefly reviews the pharmacological characteristics of caffeine, its mechanism of action in the context of encephalopathy in premature infants, and its use in the neuroprotection of encephalopathy in this patient population.
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Affiliation(s)
- Liu Yang
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China.,Department of Pediatrics, The Second Hospital of Dalian Medical University, Dalian, China
| | - Xuefei Yu
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yajun Zhang
- Department of Anesthesiology, Dalian Municipal Maternal and Child Health Care Hospital, Dalian, China
| | - Na Liu
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xindong Xue
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Jianhua Fu
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
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Lawler TP, Cialdella-Kam L. Non-carbohydrate Dietary Factors and Their Influence on Post-Exercise Glycogen Storage: a Review. Curr Nutr Rep 2020; 9:394-404. [PMID: 33128726 DOI: 10.1007/s13668-020-00335-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The optimization of post-exercise glycogen synthesis can improve endurance performance, delay fatigue in subsequent bouts, and accelerate recovery from exercise. High carbohydrate intakes (1.2 g/kg of body weight/h) are recommended in the first 4 h after exercise. However, athletes may struggle to consume carbohydrates at those levels. PURPOSE OF REVIEW: Thus, we aimed to determine whether the consumption of non-carbohydrate dietary factors (creatine, glutamine, caffeine, flavonoids, and alcohol) enhances post-exercise glycogen synthesis. RECENT FINDINGS: Trained athletes may not realize the benefits of creatine loading on glycogen synthesis. The impacts of caffeine, glutamine, flavonoids, and alcohol on post-exercise glycogen synthesis are poorly understood. Other ergogenic benefits to exercise performance, however, have been reported for creatine, glutamine, caffeine, and flavonoids, which were beyond the scope of this review. Evidence in trained athletes is limited and inconclusive on the impact of these non-carbohydrate dietary factors on post-exercise glycogen synthesis.
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Affiliation(s)
- Thomas P Lawler
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Department of Nutritional Sciences, University of Wisconsin, Madison, Madison, WI, USA
| | - Lynn Cialdella-Kam
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, OH, USA. .,Warfigther Performance Department, Naval Health Research Center, 140 Sylvester Road, San Diego, CA, 92106, USA.
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7
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Monteiro J, Alves MG, Oliveira PF, Silva BM. Pharmacological potential of methylxanthines: Retrospective analysis and future expectations. Crit Rev Food Sci Nutr 2018; 59:2597-2625. [PMID: 29624433 DOI: 10.1080/10408398.2018.1461607] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Methylated xanthines (methylxanthines) are available from a significant number of different botanical species. They are ordinarily included in daily diet, in many extremely common beverages and foods. Caffeine, theophylline and theobromine are the main methylxanthines available from natural sources. The supposedly relatively low toxicity of methylxanthines, combined with the many beneficial effects that have been attributed to these compounds through time, generated a justified attention and a very prolific ground for dedicated scientific reports. Methylxanthines have been widely used as therapeutical tools, in an intriguing range of medicinal scopes. In fact, methylxanthines have been/were medically used as Central Nervous System stimulants, bronchodilators, coronary dilators, diuretics and anti-cancer adjuvant treatments. Other than these applications, methylxanthines have also been hinted to hold other beneficial health effects, namely regarding neurodegenerative diseases, cardioprotection, diabetes and fertility. However, it seems now consensual that toxicity concerns related to methylxanthine consumption and/or therapeutic use should not be dismissed. Taking all the knowledge and expectations on the potential of methylxanthines into account, we propose a systematic look at the past and future of methylxanthine pharmacologic applications, discussing all the promise and anticipating possible constraints. Anyways, methylxanthines will still substantiate considerable meaningful research and discussion for years to come.
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Affiliation(s)
- João Monteiro
- Mass Spectrometry Centre, Department of Chemistry & CESAM, University of Aveiro, Campus Universitário de Santiago , Aveiro , Portugal
| | - Marco G Alves
- Department of Microscopy, Laboratory of Cell Biology, Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto , Porto , Portugal
| | - Pedro F Oliveira
- Department of Microscopy, Laboratory of Cell Biology, Unit for Multidisciplinary Research in Biomedicine (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto , Porto , Portugal.,Institute of Health Research an Innovation (i3S), University of Porto , Porto , Portugal
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Nakamura M, Makino Y, Takagi C, Yamagaki T, Sato M. Probing the catalytic site of rabbit muscle glycogen phosphorylase using a series of specifically modified maltohexaose derivatives. Glycoconj J 2017; 34:563-574. [PMID: 28597243 DOI: 10.1007/s10719-017-9776-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 02/05/2023]
Abstract
Glycogen phosphorylase (GP) is an allosteric enzyme whose catalytic site comprises six subsites (SG1, SG-1, SG-2, SG-3, SG-4, and SP) that are complementary to tandem five glucose residues and one inorganic phosphate molecule, respectively. In the catalysis of GP, the nonreducing-end glucose (Glc) of the maltooligosaccharide substrate binds to SG1 and is then phosphorolyzed to yield glucose 1-phosphate. In this study, we probed the catalytic site of rabbit muscle GP using pyridylaminated-maltohexaose (Glcα1-4Glcα1-4Glcα1-4Glcα1-4Glcα1-4GlcPA, where GlcPA = 1-deoxy-1-[(2-pyridyl)amino]-D-glucitol]; abbreviated as PA-0) and a series of specifically modified PA-0 derivatives (Glc m -AltNAc-Glc n -GlcPA, where m + n = 4 and AltNAc is 3-acetoamido-3-deoxy-D-altrose). PA-0 served as an efficient substrate for GP, whereas the other PA-0 derivatives were not as good as the PA-0, indicating that substrate recognition by all the SG1 -SG-4 subsites was important for the catalysis of GP. By comparing the initial reaction rate toward the PA-0 derivatives (V derivative) with that toward PA-0 (V PA-0), we found that the value of V derivative/V PA-0 decreased significantly as the level of allosteric activation of GP increased. These results suggest that some conformational changes have taken place in the maltooligosaccharide-binding region of the GP catalytic site during allosteric regulation.
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Affiliation(s)
- Makoto Nakamura
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Yasushi Makino
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka, 599-8531, Japan.
| | - Chika Takagi
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Tohru Yamagaki
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Seika-cho, Soraku-gun, Kyoto, 619-0284, Japan
| | - Masaaki Sato
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka, 599-8531, Japan
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Vieira JM, Gutierres JM, Carvalho FB, Pereira LB, Oliveira LS, Morsch VM, Schetinger MRC, Rodrigues MV, Leitemperger J, Loro V, Krewer CC, Vencato MS, Spanevello RM. Caffeine prevents changes in muscle caused by high-intensity interval training. Biomed Pharmacother 2017; 89:116-123. [DOI: 10.1016/j.biopha.2017.01.138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/16/2017] [Accepted: 01/24/2017] [Indexed: 01/22/2023] Open
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Miyagawa D, Makino Y, Sato M. Sensitive, nonradioactive assay of phosphorylase kinase through measurement of enhanced phosphorylase activity towards fluorogenic dextrin. J Biochem 2016; 159:239-46. [PMID: 26378249 PMCID: PMC4892779 DOI: 10.1093/jb/mvv097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/21/2015] [Indexed: 02/03/2023] Open
Abstract
Glycogen phosphorylase (GP) exists in two interconvertible forms, GPa (phosphorylated form, high activity) and GPb (nonphosphorylated form, low activity). Phosphorylase kinase (PhK) catalyses the phosphorylation of GPb and plays a key role in the cascade system for regulating glycogen metabolism. In this study, we developed a highly sensitive and nonradioactive assay for PhK activity by measuring the enhanced GP activity towards a pyridylaminated maltohexaose. The enhanced GP activity (ΔA) was calculated by the following formula: ΔA = A(+) - A(0), where A(+) and A(0) represent the GP activities of the PhK-treated and PhK-nontreated samples, respectively. Using a high-performance liquid chromatograph equipped with a fluorescence spectrophotometer, the product of GP activity could be isolated and quantified at 10 fmol. This method does not require the use of any radioactive compounds and only 1 µg of GPb per sample was needed to obtain A(+) and A(0) values. The remarkable reduction in GPb concentration enabled us to discuss an interesting new role for glycogen in PhK activity.
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Affiliation(s)
- Daichi Miyagawa
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Yasushi Makino
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Masaaki Sato
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8531, Japan
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Cappelletti S, Piacentino D, Daria P, Sani G, Aromatario M. Caffeine: cognitive and physical performance enhancer or psychoactive drug? Curr Neuropharmacol 2016; 13:71-88. [PMID: 26074744 PMCID: PMC4462044 DOI: 10.2174/1570159x13666141210215655] [Citation(s) in RCA: 246] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/10/2014] [Accepted: 10/25/2014] [Indexed: 02/06/2023] Open
Abstract
Caffeine use is increasing worldwide. The underlying motivations are mainly concentration
and memory enhancement and physical performance improvement. Coffee and caffeine-containing
products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and
the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects.
Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore,
caffeine abuse and dependence are becoming more and more common and can lead to caffeine
intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main
findings concerning caffeine’s mechanisms of action (focusing on adenosine antagonism, intracellular calcium
mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests
that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal
role in intoxication or death. This could be due to caffeine’s interaction with other substances or to the individuals' preexisting
metabolism alterations or diseases.
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Affiliation(s)
- Simone Cappelletti
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, "Sapienza" University of Rome, Rome, Italy
| | | | - Piacentino Daria
- NESMOS (Neuroscience, Mental Health, and Sensory Organs) Department, School of Medicine and Psychology, "Sapienza" University of Rome, Rome, Italy
| | - Gabriele Sani
- NESMOS (Neuroscience, Mental Health, and Sensory Organs) Department, School of Medicine and Psychology, "Sapienza" University of Rome, Rome, Italy
| | - Mariarosaria Aromatario
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, "Sapienza" University of Rome, Rome, Italy
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Shearer J, Graham TE. Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal. Nutr Rev 2015; 72 Suppl 1:121-36. [PMID: 25293551 DOI: 10.1111/nure.12124] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
This review documents two opposing effects of caffeine and caffeine-containing energy drinks, i.e., their positive effects on athletic performance and their negative impacts on glucose tolerance in the sedentary state. Analysis of studies examining caffeine administration prior to performance-based exercise showed caffeine improved completion time by 3.6%. Similar analyses following consumption of caffeine-containing energy drinks yielded positive, but more varied, benefits, which were likely due to the diverse nature of the studies performed, the highly variable composition of the beverages consumed, and the range of caffeine doses administered. Conversely, analyses of studies administering caffeine prior to either an oral glucose tolerance test or insulin clamp showed a decline in whole-body glucose disposal of ~30%. The consequences of this resistance are unknown, but there may be implications for the development of a number of chronic diseases. Both caffeine-induced performance enhancement and insulin resistance converge with the primary actions of caffeine on skeletal muscle.
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Affiliation(s)
- Jane Shearer
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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Lopez RJ, Mosca B, Treves S, Maj M, Bergamelli L, Calderon JC, Bentzinger CF, Romanino K, Hall MN, Rüegg MA, Delbono O, Caputo C, Zorzato F. Raptor ablation in skeletal muscle decreases Cav1.1 expression and affects the function of the excitation-contraction coupling supramolecular complex. Biochem J 2015; 466:123-35. [PMID: 25431931 PMCID: PMC4843809 DOI: 10.1042/bj20140935] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The protein mammalian target of rapamycin (mTOR) is a serine/threonine kinase regulating a number of biochemical pathways controlling cell growth. mTOR exists in two complexes termed mTORC1 and mTORC2. Regulatory associated protein of mTOR (raptor) is associated with mTORC1 and is essential for its function. Ablation of raptor in skeletal muscle results in several phenotypic changes including decreased life expectancy, increased glycogen deposits and alterations of the twitch kinetics of slow fibres. In the present paper, we show that in muscle-specific raptor knockout (RamKO), the bulk of glycogen phosphorylase (GP) is mainly associated in its cAMP-non-stimulated form with sarcoplasmic reticulum (SR) membranes. In addition, 3[H]-ryanodine and 3[H]-PN200-110 equilibrium binding show a ryanodine to dihydropyridine receptors (DHPRs) ratio of 0.79 and 1.35 for wild-type (WT) and raptor KO skeletal muscle membranes respectively. Peak amplitude and time to peak of the global calcium transients evoked by supramaximal field stimulation were not different between WT and raptor KO. However, the increase in the voltage sensor-uncoupled RyRs leads to an increase of both frequency and mass of elementary calcium release events (ECRE) induced by hyper-osmotic shock in flexor digitorum brevis (FDB) fibres from raptor KO. The present study shows that the protein composition and function of the molecular machinery involved in skeletal muscle excitation-contraction (E-C) coupling is affected by mTORC1 signalling.
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Affiliation(s)
- Rubén J. Lopez
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Barbara Mosca
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Susan Treves
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Marcin Maj
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Leda Bergamelli
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
| | - Juan C. Calderon
- Laboratorio de Fisiología Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, 1020A Caracas, Venezuela
| | | | - Klaas Romanino
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | | | | | - Osvaldo Delbono
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, U.S.A
| | - Carlo Caputo
- Laboratorio de Fisiología Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, 1020A Caracas, Venezuela
| | - Francesco Zorzato
- Departments of Anesthesia and of Biomedicine, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland
- Department of Life Sciences, General Pathology section, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
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14
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Katz A, Westerblad H. Regulation of glycogen breakdown and its consequences for skeletal muscle function after training. Mamm Genome 2014; 25:464-72. [PMID: 24777203 DOI: 10.1007/s00335-014-9519-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/02/2014] [Indexed: 02/06/2023]
Abstract
Repeated bouts of physical exercise, i.e., training, induce mitochondrial biogenesis and result in improved physical performance and attenuation of glycogen breakdown during submaximal exercise. It has been suggested that as a consequence of the increased mitochondrial volume, a smaller degree of metabolic stress (e.g., smaller increases in ADP and Pi) is required to maintain mitochondrial respiration in the trained state during exercise at the same absolute intensity. The lower degree of Pi accumulation is believed to account for the diminished glycogen breakdown, since Pi is a substrate for glycogen phosphorylase, the rate-limiting enzyme for glycogenolysis. However, in this review, we present an alternative explanation for the diminished glycogen breakdown. Thus, the lower degree of metabolic stress after training is also associated with smaller increases in AMP (free concentration during contraction at specific intracellular sites) and this results in less activation of phosphorylase b (the non-phosphorylated form of phosphorylase), resulting in diminished glycogen breakdown. Concomitantly, the smaller accumulation of Pi, which interferes with cross-bridge function and intracellular Ca(2+) handling, contributes to the increased fatigue resistance. The delay in glycogen depletion also contributes to enhanced performance during prolonged exercise by functioning as an energy reserve.
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Affiliation(s)
- Abram Katz
- School of Health Sciences, Ariel University, 40700, Ariel, Israel,
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Pesta DH, Angadi SS, Burtscher M, Roberts CK. The effects of caffeine, nicotine, ethanol, and tetrahydrocannabinol on exercise performance. Nutr Metab (Lond) 2013; 10:71. [PMID: 24330705 PMCID: PMC3878772 DOI: 10.1186/1743-7075-10-71] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/02/2013] [Indexed: 01/01/2023] Open
Abstract
Caffeine, nicotine, ethanol and tetrahydrocannabinol (THC) are among the most prevalent and culturally accepted drugs in western society. For example, in Europe and North America up to 90% of the adult population drinks coffee daily and, although less prevalent, the other drugs are also used extensively by the population. Smoked tobacco, excessive alcohol consumption and marijuana (cannabis) smoking are addictive and exhibit adverse health effects. These drugs are not only common in the general population, but have also made their way into elite sports because of their purported performance-altering potential. Only one of the drugs (i.e., caffeine) has enough scientific evidence indicating an ergogenic effect. There is some preliminary evidence for nicotine as an ergogenic aid, but further study is required; cannabis and alcohol can exhibit ergogenic potential under specific circumstances but are in general believed to be ergolytic for sports performance. These drugs are currently (THC, ethanol) or have been (caffeine) on the prohibited list of the World Anti-Doping Agency or are being monitored (nicotine) due to their potential ergogenic or ergolytic effects. The aim of this brief review is to evaluate the effects of caffeine, nicotine, ethanol and THC by: 1) examining evidence supporting the ergogenic or ergolytic effects; 2) providing an overview of the mechanism(s) of action and physiological effects; and 3) where appropriate, reviewing their impact as performance-altering aids used in recreational and elite sports.
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Affiliation(s)
- Dominik H Pesta
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
- Department of Sports Science, Medical Section, University Innsbruck, Innsbruck, Austria
| | - Siddhartha S Angadi
- Healthy Lifestyles Research Center, School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ, USA
| | - Martin Burtscher
- Department of Sports Science, Medical Section, University Innsbruck, Innsbruck, Austria
| | - Christian K Roberts
- Exercise and Metabolic Disease Research Laboratory, Translational Sciences Section, School of Nursing, University of California, Los Angeles, CA, USA
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16
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Gaboriaud-Kolar N, Skaltsounis AL. Glycogen phosphorylase inhibitors: a patent review (2008 - 2012). Expert Opin Ther Pat 2013; 23:1017-32. [PMID: 23627914 DOI: 10.1517/13543776.2013.794790] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Glycogen phosphorylase (GP) is the enzyme responsible for the synthesis of glucose-1-phosphate, the source of energy for muscles and the rest of the body. The binding of different ligands in catalytic or allosteric sites assures activation and deactivation of the enzyme. A description of the regulation mechanism and the implications in glycogen metabolism are given. AREAS COVERED Deregulation of GP has been observed in diseases such as diabetes mellitus or cancers. Therefore, it appears as an attractive therapeutic target for the treatment of such pathologies. Numbers of inhibitors have been published in academic literature or patented in the last two decades. This review presents the main patent claims published between 2008 and 2012. EXPERT OPINION Good inhibitors with interesting IC50 and in vivo results are presented. However, such therapeutic strategy raises questions and some answers are proposed to bring new insights in the field.
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17
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Beaudoin MS, Graham TE. Methylxanthines and human health: epidemiological and experimental evidence. Handb Exp Pharmacol 2011:509-548. [PMID: 20859811 DOI: 10.1007/978-3-642-13443-2_21] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
When considering methylxanthines and human health, it must be recognized that in many countries most caffeine is consumed as coffee. This is further confounded by the fact that coffee contains many bioactive substances in addition to caffeine; it is rich in phenols (quinides, chlorogenic acid, and lactones) and also has diterpenes (fatty acid esters), potassium, niacin, magnesium, and the vitamin B(3) precursor trigonelline. There is a paradox as consumption of either caffeine or caffeinated coffee results in a marked insulin resistance and yet habitual coffee consumption has repeatedly been reported to markedly reduce the risk for type 2 diabetes. There is strong evidence that caffeine reduces insulin sensitivity in skeletal muscle and this may be due to a combination of direct antagonism of A(1) receptors and indirectly β-adrenergic stimulation as a result of increased sympathetic activity. Caffeine may also induce reduced hepatic glucose output. With the exception of bone mineral, there is little evidence that caffeine impacts negatively on other health issues. Coffee does not increase the risk of cardiovascular diseases or cancers and there is some evidence suggesting a positive relationship for the former and for some cancers, particularly hepatic cancer.
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Affiliation(s)
- Marie-Soleil Beaudoin
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada, N1G 2W1
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18
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Guttierres APM, Natali AJ, Alfenas RDCG, Marins JCB. Efeito ergogênico de uma bebida esportiva cafeinada sobre a performance em testes de habilidades específicas do futebol. REV BRAS MED ESPORTE 2009. [DOI: 10.1590/s1517-86922009000700010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
O consumo de cafeína tem demonstrado promover efeitos ergogênicos sobre a performance de atletas de esportes coletivos. O objetivo do presente estudo foi comparar o efeito de uma bebida esportiva cafeinada (BEC) frente a uma bebida carboidratada comercial (BCC) sobre a performance durante a execução de testes físico-motores de habilidades específicas do futebol. Os atletas foram submetidos a dois testes, salto vertical (Sargent Jump) e teste de agilidade (Illinois Agility Test), que foram executados antes e após as partidas durante as quais foram consumidas BEC (7% de carboidratos (CHO), concentração de cafeína correspondente a 250mg.l-1) ou BCC (sem cafeína, 7% de CHO). Os resultados demonstraram que BEC aumentou significantemente (p < 0,01) a altura atingida no salto em relação ao momento anterior ao seu consumo e em comparação com a BCC (p = 0,02). BCC não promoveu aumento na potência de membros inferiores. Tanto BEC (p = 0,62) quanto BCC (p = 0,93), não aumentaram a agilidade no teste realizado após a partida em comparação com o realizado anteriormente. Ambas as bebidas não foram capazes de melhorar o desempenho na execução do teste de agilidade após a partida (p = 0,95). O consumo de BEC proporcionou um efeito ergogênico para jogadores de futebol, aumentando a potência de membros inferiores relacionada com a força explosiva. Contudo, quanto à agilidade não foi possível identificar vantagens no desempenho.
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19
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Graham TE, Battram DS, Dela F, El-Sohemy A, Thong FSL. Does caffeine alter muscle carbohydrate and fat metabolism during exercise? Appl Physiol Nutr Metab 2009; 33:1311-8. [PMID: 19088793 DOI: 10.1139/h08-129] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Caffeine, an adenosine receptor antagonist, has been studied for decades as a putative ergogenic aid. In the past 2 decades, the information has overwhelmingly demonstrated that it indeed is a powerful ergogenic aid, and frequently theories have been proposed that this is due to alterations in fat and carbohydrate metabolism. While caffeine certainly mobilizes fatty acids from adipose tissue, rarely have measures of the respiratory exchange ratio indicated an increase in fat oxidation. However, this is a difficult measure to perform accurately during exercise, and small changes could be physiologically important. The few studies examining human muscle metabolism directly have also supported the fact that there is no change in fat or carbohydrate metabolism, but these usually have had a small sample size. We combined the data from muscle biopsy analyses of several similar studies to generate a sample size of 16-44, depending on the measure. We examined muscle glycogen, citrate, acetyl-CoA, glucose-6-phosphate, and cyclic adenosine monophosphate (cAMP) in resting samples and in those obtained after 10-15 min of exercise at 70%-85% maximal oxygen consumption. Exercise decreased (p < 0.05) glycogen and increased (p < 0.05) citrate, acetyl-CoA, and glucose-6-phosphate. The only effects of caffeine were to increase (p < 0.05) citrate in resting muscle and cAMP in exercise. There is very little evidence to support the hypothesis that caffeine has ergogenic effects as a result of enhanced fat oxidation. Individuals may, however, respond differently to the effects of caffeine, and there is growing evidence that this could be explained by common genetic variations.
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Affiliation(s)
- Terry E Graham
- Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G2W1, Canada.
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20
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Perry CGR, Heigenhauser GJF, Bonen A, Spriet LL. High-intensity aerobic interval training increases fat and carbohydrate metabolic capacities in human skeletal muscle. Appl Physiol Nutr Metab 2009; 33:1112-23. [PMID: 19088769 DOI: 10.1139/h08-097] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
High-intensity aerobic interval training (HIIT) is a compromise between time-consuming moderate-intensity training and sprint-interval training requiring all-out efforts. However, there are few data regarding the ability of HIIT to increase the capacities of fat and carbohydrate oxidation in skeletal muscle. Using untrained recreationally active individuals, we investigated skeletal muscle and whole-body metabolic adaptations that occurred following 6 weeks of HIIT (~1 h of 10 x 4 min intervals at ~90% of peak oxygen consumption (VO2 peak), separated by 2 min rest, 3 d.week-1). A VO2 peak test, a test to exhaustion (TE) at 90% of pre-training VO2 peak, and a 1 h cycle at 60% of pre-training VO2 peak were performed pre- and post-HIIT. Muscle biopsies were sampled during the TE at rest, after 5 min, and at exhaustion. Training power output increased by 21%, and VO2 peak increased by 9% following HIIT. Muscle adaptations at rest included the following: (i) increased cytochrome c oxidase IV content (18%) and maximal activities of the mitochondrial enzymes citrate synthase (26%), beta-hydroxyacyl-CoA dehydrogenase (29%), aspartate-amino transferase (26%), and pyruvate dehydrogenase (PDH; 21%); (ii) increased FAT/CD36, FABPpm, GLUT 4, and MCT 1 and 4 transport proteins (14%-30%); and (iii) increased glycogen content (59%). Major adaptations during exercise included the following: (i) reduced glycogenolysis, lactate accumulation, and substrate phosphorylation (0-5 min of TE); (ii) unchanged PDH activation (carbohydrate oxidation; 0-5 min of TE); (iii) ~2-fold greater time during the TE; and (iv) increased fat oxidation at 60% of pre-training VO2 peak. This study demonstrated that 18 h of repeated high-intensity exercise sessions over 6 weeks (3 d.week-1) is a powerful method to increase whole-body and skeletal muscle capacities to oxidize fat and carbohydrate in previously untrained individuals.
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Affiliation(s)
- Christopher G R Perry
- Department of Human Health and Nutritional Sciences, University of Guelph, ON N1G 2W1, Canada.
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21
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Pedersen DJ, Lessard SJ, Coffey VG, Churchley EG, Wootton AM, Ng T, Watt MJ, Hawley JA. High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine. J Appl Physiol (1985) 2008; 105:7-13. [PMID: 18467543 DOI: 10.1152/japplphysiol.01121.2007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We determined the effect of coingestion of caffeine (Caff) with carbohydrate (CHO) on rates of muscle glycogen resynthesis during recovery from exhaustive exercise in seven trained subjects who completed two experimental trials in a randomized, double-blind crossover design. The evening before an experiment subjects performed intermittent exhaustive cycling and then consumed a low-CHO meal. The next morning subjects rode until volitional fatigue. On completion of this ride subjects consumed either CHO [4 g/kg body mass (BM)] or the same amount of CHO + Caff (8 mg/kg BM) during 4 h of passive recovery. Muscle biopsies and blood samples were taken at regular intervals throughout recovery. Muscle glycogen levels were similar at exhaustion [ approximately 75 mmol/kg dry wt (dw)] and increased by a similar amount ( approximately 80%) after 1 h of recovery (133 +/- 37.8 vs. 149 +/- 48 mmol/kg dw for CHO and Caff, respectively). After 4 h of recovery Caff resulted in higher glycogen accumulation (313 +/- 69 vs. 234 +/- 50 mmol/kg dw, P < 0.001). Accordingly, the overall rate of resynthesis for the 4-h recovery period was 66% higher in Caff compared with CHO (57.7 +/- 18.5 vs. 38.0 +/- 7.7 mmol x kg dw(-1) x h(-1), P < 0.05). After 1 h of recovery plasma Caff levels had increased to 31 +/- 11 microM (P < 0.001) and at the end of the recovery reached 77 +/- 11 microM (P < 0.001) with Caff. Phosphorylation of CaMK(Thr286) was similar after exercise and after 1 h of recovery, but after 4 h CaMK(Thr286) phosphorylation was higher in Caff than CHO (P < 0.05). Phosphorylation of AMP-activated protein kinase (AMPK)(Thr172) and Akt(Ser473) was similar for both treatments at all time points. We provide the first evidence that in trained subjects coingestion of large amounts of Caff (8 mg/kg BM) with CHO has an additive effect on rates of postexercise muscle glycogen accumulation compared with consumption of CHO alone.
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Affiliation(s)
- David J Pedersen
- School of Medical Sciences, RMIT University, Bundoora 3083, Victoria, Australia
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22
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Green HJ, Duhamel TA, Holloway GP, Moule J, Ouyang J, Ranney D, Tupling AR. Muscle metabolic responses during 16 hours of intermittent heavy exercise. Can J Physiol Pharmacol 2007; 85:634-45. [PMID: 17823626 DOI: 10.1139/y07-039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The alterations in muscle metabolism were investigated in response to repeated sessions of heavy intermittent exercise performed over 16 h. Tissue samples were extracted from the vastus lateralis muscle before (B) and after (A) 6 min of cycling at approximately 91% peak aerobic power at repetitions one (R1), two (R2), nine (R9), and sixteen (R16) in 13 untrained volunteers (peak aerobic power = 44.3 +/- 0.66 mL.kg-1.min-1, mean +/- SE). Metabolite content (mmol.(kg dry mass)-1) in homogenates at R1 indicated decreases (p < 0.05) in ATP (21.9 +/- 0.62 vs. 17.7 +/- 0.68) and phosphocreatine (80.3 +/- 2.0 vs. 8.56 +/- 1.5) and increases (p < 0.05) in inosine monophosphate (IMP, 0.077 +/- 0.12 vs. 3.63 +/- 0.85) and lactate (3.80 +/- 0.57 vs. 84.6 +/- 10.3). The content (micromol.(kg dry mass)-1) of calculated free ADP ([ADPf], 86.4 +/- 5.5 vs. 1014 +/- 237) and free AMP ([AMPf], 0.32 +/- 0.03 vs. 78.4 +/- 31) also increased (p < 0.05). No differences were observed between R1 and R2. By R9 and continuing to R16, pronounced reductions (p < 0.05) at A were observed in IMP (72.2%), [ADPf] (58.7%), [AMPf] (85.5%), and lactate (41.3%). The 16-hour protocol resulted in an 89.7% depletion (p < 0.05) of muscle glycogen. Repetition-dependent increases were also observed in oxygen consumption during exercise. It is concluded that repetitive heavy exercise results in less of a disturbance in phosphorylation potential, possibly as a result of increased mitochondrial respiration during the rest-to-work non-steady-state transition.
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Affiliation(s)
- H J Green
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
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23
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Freeman S, Bartlett JB, Convey G, Hardern I, Teague JL, Loxham SJG, Allen JM, Poucher SM, Charles AD. Sensitivity of glycogen phosphorylase isoforms to indole site inhibitors is markedly dependent on the activation state of the enzyme. Br J Pharmacol 2006; 149:775-85. [PMID: 17016495 PMCID: PMC2014651 DOI: 10.1038/sj.bjp.0706925] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Inhibition of hepatic glycogen phosphorylase is a potential treatment for glycaemic control in type 2 diabetes. Selective inhibition of the liver phosphorylase isoform could minimize adverse effects in other tissues. We investigated the potential selectivity of two indole site phosphorylase inhibitors, GPi688 and GPi819. EXPERIMENTAL APPROACH The activity of glycogen phosphorylase was modulated using the allosteric effectors glucose or caffeine to promote the less active T state, and AMP to promote the more active R state. In vitro potency of indole site inhibitors against liver and muscle glycogen phosphorylase a was examined at different effector concentrations using purified recombinant enzymes. The potency of GPi819 was compared with its in vivo efficacy at raising glycogen concentrations in liver and muscle of Zucker (fa/fa) rats. KEY RESULTS In vitro potency of indole site inhibitors depended upon the activity state of phosphorylase a. Both inhibitors showed selectivity for liver phosphorylase a when the isoform specific activities were equal. After 5 days dosing of GPi819 (37.5 micromol kg(-1)), where free compound levels in plasma and tissue were at steady state, glycogen elevation was 1.5-fold greater in soleus muscle than in liver (P < 0.05). CONCLUSIONS AND IMPLICATIONS The in vivo selectivity of GPi819 did not match that seen in vitro when the specific activities of phosphorylase a isoforms are equal. This suggests T state promoters may be important physiological regulators in skeletal muscle. The greater efficacy of indole site inhibitors in skeletal muscle has implications for the overall safety profile of such drugs.
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Affiliation(s)
- S Freeman
- Cardiovascular and Gastrointestinal Discovery Department, AstraZeneca, Macclesfield, Cheshire, UK.
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Hadjicharalambous M, Georgiades E, Kilduff LP, Turner AP, Tsofliou F, Pitsiladis YP. Influence of caffeine on perception of effort, metabolism and exercise performance following a high-fat meal. J Sports Sci 2006; 24:875-87. [PMID: 16815783 DOI: 10.1080/02640410500249399] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This study examined the effects of caffeine, co-ingested with a high fat meal, on perceptual and metabolic responses during incremental (Experiment 1) and endurance (Experiment 2) exercise performance. Trained participants performed three constant-load cycling tests at approximately 73% of maximal oxygen uptake (VO2max) for 30 min at 20 degrees C (Experiment 1, n = 8) and to the limit of tolerance at 10 degrees C (Experiment 2, n = 10). The 30 min constant-load exercise in Experiment 1 was followed by incremental exercise (15 W . min-1) to fatigue. Four hours before the first test, the participants consumed a 90% carbohydrate meal (control trial); in the remaining two tests, the participants consumed a 90% fat meal with (fat + caffeine trial) and without (fat-only trial) caffeine. Caffeine and placebo were randomly assigned and ingested 1 h before exercise. In both experiments, ratings of perceived leg exertion were significantly lower during the fat + caffeine than fat-only trial (Experiment 1: P < 0.001; Experiment 2: P < 0.01). Ratings of perceived breathlessness were significantly lower in Experiment 1 (P < 0.01) and heart rate higher in Experiment 2 (P < 0.001) on the fat + caffeine than fat-only trial. In the two experiments, oxygen uptake, ventilation, blood [glucose], [lactate] and plasma [glycerol] were significantly higher on the fat + caffeine than fat-only trial. In Experiment 2, plasma [free fatty acids], blood [pyruvate] and the [lactate]:[pyruvate] ratio were significantly higher on the fat + caffeine than fat-only trial. Time to exhaustion during incremental exercise (Experiment 1: control: 4.9, s = 1.8 min; fat-only: 5.0, s = 2.2 min; fat + caffeine: 5.0, s = 2.2 min; P > 0.05) and constant-load exercise (Experiment 2: control: 116 (88 - 145) min; fat-only: 122 (96 - 144) min; fat + caffeine: 127 (107 - 176) min; P > 0.05) was not different between the fat-only and fat + caffeine trials. In conclusion, while a number of metabolic responses were increased during exercise after caffeine ingestion, perception of effort was reduced and this may be attributed to the direct stimulatory effect of caffeine on the central nervous system. However, this caffeine-induced reduction in effort perception did not improve exercise performance.
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Sangiao-Alvarellos S, Arjona FJ, Martín del Río MP, Míguez JM, Mancera JM, Soengas JL. Time course of osmoregulatory and metabolic changes during osmotic acclimation in Sparus auratus. ACTA ACUST UNITED AC 2006; 208:4291-304. [PMID: 16272252 DOI: 10.1242/jeb.01900] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Changes in different osmoregulatory and metabolic parameters over time were assessed in gills, kidney, liver and brain of gilthead sea bream Sparus auratus transferred either from seawater (SW, 38 p.p.t.) to hypersaline water (HSW, 55 p.p.t.) or from SW to low salinity water (LSW, 6 p.p.t.) for 14 days. Changes displayed by osmoregulatory parameters revealed two stages during hyperosmotic and hypo-osmotic acclimation: (i) an adaptive period during the first days of acclimation (1-3 days), with important changes in these parameters, and (ii) a chronic regulatory period (after 3 days of transfer) where osmotic parameters reached homeostasis. From a metabolic point of view, two clear phases can also be distinguished during acclimation to hyperosmotic or hypo-osmotic conditions. The first one coincides with the adaptive period and is characterized by enhanced levels of plasma metabolites (glucose, lactate, triglycerides and protein), and use of these metabolites by different tissues in processes directly or indirectly involved in osmoregulatory work. The second stage coincides with the chronic regulatory period observed for the osmoregulatory parameters and is metabolically characterized in HSW-transferred fish by lower energy expenditure and a readjustment of metabolic parameters to levels returning to normality, indicative of reduced osmoregulatory work in this stage. In LSW-transferred fish, major changes in the second stage include: (i) decreased glycolytic potential, capacity for exporting glucose and potential for amino acid catabolism in liver; (ii) enhanced use of exogenous glucose through glycolysis, pentose phosphate and glycogenesis in gills; (iii) increased glycolytic potential in kidney; and (iv) increased glycogenolytic potential and capacity for use of exogenous glucose in brain.
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Affiliation(s)
- Susana Sangiao-Alvarellos
- Laboratorio de Fisioloxía Animal, Facultade de Ciencias do Mar, Universidade de Vigo, 36310 Vigo, Spain
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Camacho RC, Donahue EP, James FD, Berglund ED, Wasserman DH. Energy state of the liver during short-term and exhaustive exercise in C57BL/6J mice. Am J Physiol Endocrinol Metab 2006; 290:E405-8. [PMID: 16219665 DOI: 10.1152/ajpendo.00385.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A portal venous 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside infusion that results in hepatic 5-aminoimidazole-4-carboxamide-1-beta-D-ribosyl-5-monophosphate (ZMP) concentrations of approximately 4 micromol/g liver increases hepatic glycogenolysis and glucose output. ZMP is an AMP analog that mimics the regulatory actions of this nucleotide. The aim of this study was to measure hepatic AMP concentrations in response to increasing energy requirements to test the hypothesis that AMP achieves concentrations during exercise, consistent with a role in stimulation of hepatic glucose metabolism. Male C57BL/6J mice (27.4+/- 0.4 g) were subjected to 35 min of rest [sedentary (SED), n=8], underwent short-term (ST, 35 min) moderate (20 m/min, 5% grade) exercise (n=8), or underwent treadmill exercise under similar conditions but until exhaustion (EXH, n=8). Hepatic AMP concentrations were 0.82+/- 0.05, 1.17+/- 0.11, and 2.52+/- 0.16 micromol/g liver in SED, ST, and EXH mice, respectively (P< 0.05). Hepatic energy charge was 0.66+/- 0.01, 0.58+/- 0.02, and 0.33+/- 0.22 in SED, ST, and EXH mice, respectively (P< 0.05). Hepatic glycogen was 11.6+/- 1.0, 8.8+/- 2.2, and 0.0+/- 0.1 mg/g liver in SED, ST, and EXH mice, respectively (P< 0.05). Hepatic AMPK (Thr(172)) phosphorylation was 1.00+/- 0.14, 1.96+/- 0.16, and 7.44+/- 0.63 arbitrary units in SED, ST, and EXH mice, respectively (P< 0.05). Thus exercise increases hepatic AMP concentrations. These data suggest that the liver is highly sensitive to metabolic demands, as evidenced by dramatic changes in cellular energy indicators (AMP) and sensors thereof (AMP-activated protein kinase). In conclusion, AMP is sensitively regulated, consistent with it having an important role in hepatic metabolism.
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Affiliation(s)
- Raul C Camacho
- Department of Molecular Physiology and Biolphysics and Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine, Nashville, TN, USA.
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Magkos F, Kavouras SA. Caffeine Use in Sports, Pharmacokinetics in Man, and Cellular Mechanisms of Action. Crit Rev Food Sci Nutr 2005; 45:535-62. [PMID: 16371327 DOI: 10.1080/1040-830491379245] [Citation(s) in RCA: 202] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Caffeine is the most widely consumed psychoactive 'drug' in the world and probably one of the most commonly used stimulants in sports. This is not surprising, since it is one of the few ergogenic aids with documented efficiency and minimal side effects. Caffeine is rapidly and completely absorbed by the gastrointestinal tract and is readily distributed throughout all tissues of the body. Peak plasma concentrations after normal consumption are usually around 50 microM, and half-lives for elimination range between 2.5-10 h. The parent compound is extensively metabolized in the liver microsomes to more than 25 derivatives, while considerably less than 5% of the ingested dose is excreted unchanged in the urine. There is, however, considerable inter-individual variability in the handling of caffeine by the body, due to both environmental and genetic factors. Evidence from in vitro studies provides a wealth of different cellular actions that could potentially contribute to the observed effects of caffeine in humans in vivo. These include potentiation of muscle contractility via induction of sarcoplasmic reticulum calcium release, inhibition of phosphodiesterase isoenzymes and concomitant cyclic monophosphate accumulation, inhibition of glycogen phosphorylase enzymes in liver and muscle, non-selective adenosine receptor antagonism, stimulation of the cellular membrane sodium/potassium pump, impairment of phosphoinositide metabolism, as well as other, less thoroughly characterized actions. Not all, however, seem to account for the observed effects in vivo, although a variable degree of contribution cannot be readily discounted on the basis of experimental data. The most physiologically relevant mechanism of action is probably the blockade of adenosine receptors, but evidence suggests that, at least under certain conditions, other biochemical mechanisms may also be operational.
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Affiliation(s)
- Faidon Magkos
- Laboratory of Nutrition and Clinical Dietetics, Department of Nutrition and Dietetics, Harokopio University, 176 71 Kallithea, Athens, Greece
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Savage KA, Colahan PT, Tebbett IR, Rice BL, Freshwater LL, Jackson CA. Effects of caffeine on exercise performance of physically fit Thoroughbreds. Am J Vet Res 2005; 66:569-73. [PMID: 15900934 DOI: 10.2460/ajvr.2005.66.569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effects of a dose of caffeine (2.5 mg/kg, IV) administered to physically fit Thoroughbreds during incremental exercise testing to fatigue on a treadmill. ANIMALS 10 conditioned Thoroughbreds. PROCEDURE Horses were randomly assigned to receive caffeine or a control solution. Each horse received both treatments in a crossover design with a 3-week interval between treatments. Each horse was administered caffeine (2.5 mg/kg) or an equivalent amount of a control solution IV. One hour after injection, each horse performed an incremental exercise test to exhaustion. Hematologic values, heart rate, oxygen consumption, carbon dioxide production, plasma lactate concentration, urine and serum concentrations of caffeine and metabolites, and time until exhaustion were monitored. Statistical analysis was performed by use of a mixed-effects linear model. RESULTS Significant differences in measured values when horses were treated with caffeine or the control solution were not detected. CONCLUSIONS AND CLINICAL RELEVANCE A dose of caffeine (2.5 mg/kg, IV) appears to have no effect on any performance variable of physically fit Thoroughbreds during incremental exercise testing to fatigue.
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Affiliation(s)
- Kathleen A Savage
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0136, USA
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Leblanc PJ, Howarth KR, Gibala MJ, Heigenhauser GJF. Effects of 7 wk of endurance training on human skeletal muscle metabolism during submaximal exercise. J Appl Physiol (1985) 2004; 97:2148-53. [PMID: 15220302 DOI: 10.1152/japplphysiol.00517.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This is the first study to examine the effects of endurance training on the activation state of glycogen phosphorylase (Phos) and pyruvate dehydrogenase (PDH) in human skeletal muscle during exercise. We hypothesized that 7 wk of endurance training (Tr) would result in a posttransformationally regulated decrease in flux through Phos and an attenuated activation of PDH during exercise due to alterations in key allosteric modulators of these important enzymes. Eight healthy men (22 +/- 1 yr) cycled to exhaustion at the same absolute workload (206 +/- 5 W; approximately 80% of initial maximal oxygen uptake) before and after Tr. Muscle biopsies (vastus lateralis) were obtained at rest and after 5 and 15 min of exercise. Fifteen minutes of exercise post-Tr resulted in an attenuated activation of PDH (pre-Tr: 3.75 +/- 0.48 vs. post-Tr: 2.65 +/- 0.38 mmol.min(-1).kg wet wt(-1)), possibly due in part to lower pyruvate content (pre-Tr: 0.94 +/- 0.14 vs. post-Tr: 0.46 +/- 0.03 mmol/kg dry wt). The decreased pyruvate availability during exercise post-Tr may be due to a decreased muscle glycogenolytic rate (pre-Tr: 13.22 +/- 1.01 vs. post-Tr: 7.36 +/- 1.26 mmol.min(-1).kg dry wt(-1)). Decreased glycogenolysis was likely mediated, in part, by posttransformational regulation of Phos, as evidenced by smaller net increases in calculated muscle free ADP (pre-Tr: 111 +/- 16 vs. post-Tr: 84 +/- 10 micromol/kg dry wt) and P(i) (pre-Tr: 57.1 +/- 7.9 vs. post-Tr: 28.6 +/- 5.6 mmol/kg dry wt). We have demonstrated for the first time that several signals act to coordinately regulate Phos and PDH, and thus carbohydrate metabolism, in human skeletal muscle after 7 wk of endurance training.
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Affiliation(s)
- Paul J Leblanc
- Department of Medicine, McMaster University Health Science Centre, Hamilton, ON, Canada L8N 3Z5
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Abstract
For much of the 20th century, lactate was largely considered a dead-end waste product of glycolysis due to hypoxia, the primary cause of the O2 debt following exercise, a major cause of muscle fatigue, and a key factor in acidosis-induced tissue damage. Since the 1970s, a 'lactate revolution' has occurred. At present, we are in the midst of a lactate shuttle era; the lactate paradigm has shifted. It now appears that increased lactate production and concentration as a result of anoxia or dysoxia are often the exception rather than the rule. Lactic acidosis is being re-evaluated as a factor in muscle fatigue. Lactate is an important intermediate in the process of wound repair and regeneration. The origin of elevated [lactate] in injury and sepsis is being re-investigated. There is essentially unanimous experimental support for a cell-to-cell lactate shuttle, along with mounting evidence for astrocyte-neuron, lactate-alanine, peroxisomal and spermatogenic lactate shuttles. The bulk of the evidence suggests that lactate is an important intermediary in numerous metabolic processes, a particularly mobile fuel for aerobic metabolism, and perhaps a mediator of redox state among various compartments both within and between cells. Lactate can no longer be considered the usual suspect for metabolic 'crimes', but is instead a central player in cellular, regional and whole body metabolism. Overall, the cell-to-cell lactate shuttle has expanded far beyond its initial conception as an explanation for lactate metabolism during muscle contractions and exercise to now subsume all of the other shuttles as a grand description of the role(s) of lactate in numerous metabolic processes and pathways.
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Affiliation(s)
- L B Gladden
- Department of Health and Human Performance, 2050 Memorial Coliseum, Auburn University, Auburn, AL 36849-5323, USA.
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Steinberg GR, Rush JWE, Dyck DJ. AMPK expression and phosphorylation are increased in rodent muscle after chronic leptin treatment. Am J Physiol Endocrinol Metab 2003; 284:E648-54. [PMID: 12441311 DOI: 10.1152/ajpendo.00318.2002] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We have previously reported that chronic leptin administration (2 wk) increases fatty acid (FA) oxidation and triacylglycerol hydrolysis in rodent soleus muscle. Acute stimulation of AMP-activated protein kinase (AMPK) results in a repartitioning of FA toward oxidation and away from esterification in rodent soleus muscle and has recently been shown to be responsible, at least in part, for the acute stimulatory effect of leptin on FA oxidation. Therefore, we hypothesized that the effects of chronic leptin treatment on muscle FA metabolism are mediated in part through an increased expression and/or activation of AMPK and a subsequent phosphorylation of acetyl-CoA carboxylase and a decrease in malonyl-CoA content. Female Sprague-Dawley rats were infused for 2 wk with leptin (0.5 mg x kg(-1) x day(-1)) using subcutaneously implanted mini-osmotic pumps. Control and pair-fed animals received saline-filled implants. Leptin levels were elevated approximately fourfold (P < 0.001) in treated animals, relative to controls. Chronic leptin treatment resulted in an approximately 2- to 3-fold greater protein expression of AMPK catalytic (alpha(2)) and regulatory (beta(2)) units as well as a 1.5- to 2-fold increase in Thr(172) phosphorylation of AMPK in both soleus and white gastrocnemius muscles. The increased expression/phosphorylation of AMPK was not the result of an altered energy status of the muscle. Correspondingly, there was also a 1.5- to 2-fold increase in acetyl-CoA carboxylase (ACC) phosphorylation after leptin treatment in soleus and white gastrocnemius. In spite of the measured increase in ACC phosphorylation after leptin treatment, we were unable to detect a decrease in resting malonyl-CoA content in either muscle. However, taken as a whole, our data support recent evidence in rodent muscle that leptin stimulates FA oxidation through stimulation of AMPK and a subsequent downregulation of ACC activity.
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Affiliation(s)
- Gregory R Steinberg
- Department of Human Biology and Nutritional Sciences, University of Guelph, Ontario, Canada
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