Acute responses in muscle mitochondrial and cytosolic enzyme activities during heavy intermittent exercise

2008 ◽  
Vol 104 (4) ◽  
pp. 931-937 ◽  
Author(s):  
H. J. Green ◽  
E. B. Bombardier ◽  
T. A. Duhamel ◽  
G. P. Holloway ◽  
A. R. Tupling ◽  
...  

To examine the effects of repetitive bouts of heavy exercise on the maximal activities of enzymes representative of the major metabolic pathways and segments, 13 untrained volunteers [peak aerobic power (V̇o2 peak) = 44.3 ± 2.3 ml·kg−1·min−1] cycled at ∼91% V̇o2 peak for 6 min once per hour for 16 h. Maximal enzyme activities ( Vmax, mol·kg−1·protein·h−1) were measured in homogenates from tissue extracted from the vastus lateralis before and after exercise at repetitions 1 (R1), 2 (R2), 9 (R9), and 16 (R16). For the mitochondrial enzymes, exercise resulted in reductions ( P < 0.05) in cytochrome- c oxidase (COX, 14.6%), near significant reductions in malate dehydrogenase (4.06%; P = 0.06) and succinic dehydrogenase (4.82%; P = 0.09), near significant increases in β-hydroxyacyl-CoA dehydrogenase (4.94%; P = 0.08), and no change in citrate synthase (CS, 2.88%; P = 0.37). For the cytosolic enzymes, exercise reduced ( P < 0.05) Vmax in hexokinase (Hex, 4.4%), creatine phosphokinase (9.0%), total phosphorylase (13.5%), phosphofructokinase (16.6%), pyruvate kinase (PK, 14.1%) and lactate dehydrogenase (10.7%). Repetition-dependent reductions ( P < 0.05) in Vmax were observed for CS (R1, R2 > R16), COX (R1, R2 > R16), Hex (1R, 2R > R16), and PK (R9 > R16). It is concluded that heavy exercise results in transient reductions in a wide range of enzymes involved in different metabolic functions and that in the case of selected enzymes, multiple repetitions of the exercise reduce average Vmax.

2000 ◽  
Vol 88 (2) ◽  
pp. 634-640 ◽  
Author(s):  
Howard Green ◽  
Brian Roy ◽  
Susan Grant ◽  
Margaret Burnett ◽  
Russ Tupling ◽  
...  

To investigate the hypothesis that acclimatization to altitude would result in a downregulation in muscle Na+-K+-ATPase pump concentration, tissue samples were obtained from the vastus lateralis muscle of six volunteers (5 males and 1 female), ranging in age from 24 to 35 yr, both before and within 3 days after a 21-day expedition to the summit of Mount Denali, Alaska (6,194 m). Na+-K+-ATPase, measured by the [3H]ouabain-binding technique, decreased by 13.8% [348 ± 12 vs. 300 ± 7.6 (SE) pmol/g wet wt; P< 0.05]. No changes were found in the maximal activities (mol ⋅ kg protein− 1 ⋅ h− 1) of the mitochondrial enzymes, succinic dehydrogenase (3.63 ± 0.20 vs. 3.25 ± 0.23), citrate synthase (4.76 ± 0.44 vs. 4.94 ± 0.44), and malate dehydrogenase (12.6 ± 1.8 vs. 12.7 ± 1.2). Similarly, the expedition had no effect on any of the histochemical properties examined, namely fiber-type distribution (types I, IIA, IIB, IC, IIC, IIAB), area, capillarization, and succinic dehydrogenase activity. Peak aerobic power (52.3 ± 2.1 vs. 50.6 ± 1.9 ml ⋅ kg− 1 ⋅ min− 1) and body mass (76.9 ± 3.7 vs. 75.5 ± 2.9 kg) were also unaffected. We concluded that acclimatization to altitude results in a downregulation in muscle Na+-K+-ATPase pump concentration, which occurs without changes in oxidative potential and other fiber-type histochemical properties.


1992 ◽  
Vol 72 (2) ◽  
pp. 484-491 ◽  
Author(s):  
H. J. Green ◽  
R. Helyar ◽  
M. Ball-Burnett ◽  
N. Kowalchuk ◽  
S. Symon ◽  
...  

To determine whether increases in muscle mitochondrial capacity are necessary for the characteristic lower exercise glycogen loss and lactate concentration observed during exercise in the trained state, we have employed a short-term training model involving 2 h of cycling per day at 67% maximal O2 uptake (VO2max) for 5–7 consecutive days. Before and after training, biopsies were extracted from the vastus lateralis of nine male subjects during a continuous exercise challenge consisting of 30 min of work at 67% VO2max followed by 30 min at 76% VO2max. Analysis of samples at 0, 15, 20, and 60 min indicated a pronounced reduction (P less than 0.05) in glycogen utilization after training. Reductions in glycogen utilization were accompanied by reductions (P less than 0.05) in muscle lactate concentration (mmol/kg dry wt) at 15 min [37.4 +/- 9.3 (SE) vs. 20.2 +/- 5.3], 30 min (30.5 +/- 6.9 vs. 17.6 +/- 3.8), and 60 min (26.5 +/- 5.8 vs. 17.8 +/- 3.5) of exercise. Maximal aerobic power, VO2max (l/min) was unaffected by the training (3.99 +/- 0.21 vs. 4.05 +/- 0.26). Measurements of maximal activities of enzymes representative of the citric acid cycle (succinic dehydrogenase and citrate synthase) were similar before and after the training. It is concluded that, in the voluntary exercising human, altered metabolic events are an early adaptive response to training and need not be accompanied by changes in muscle mitochondrial capacity.


1999 ◽  
Vol 86 (2) ◽  
pp. 450-454 ◽  
Author(s):  
Emma C. Starritt ◽  
Damien Angus ◽  
Mark Hargreaves

Seven untrained volunteers [3 men, 4 women, 20.1 ± 2.0 (SD) yr, 66.0 ± 11.0 kg, 171 ± 13 cm] participated in a 10-day cycle exercise training program. Resting muscle samples were obtained from vastus lateralis before and after 5 and 10 days of training. Mitochondrial ATP production rate (MAPR) was assayed in isolated mitochondria by using a bioluminescence technique and referenced to the activity of glutamate dehydrogenase in the muscle sample. MAPR increased 136 and 161% after 10 days of training for the mitochondrial substrate combinations pyruvate + palmitoyl-l-carnitine + α-ketoglutarate + malate and palmitoyl-l-carnitine + malate, respectively. Total muscle glutamate dehydrogenase and citrate synthase activity increased 53 and 16%, respectively, after 5 days but did not significantly increase further after 10 days. The results from the present study indicate that MAPR, measured by using the substrate combinations pyruvate + palmitoyl-l-carnitine + α-ketoglutarate + malate and palmitoyl-l-carnitine + malate, can rapidly increase in response to endurance training.


1992 ◽  
Vol 73 (5) ◽  
pp. 2004-2010 ◽  
Author(s):  
R. Wibom ◽  
E. Hultman ◽  
M. Johansson ◽  
K. Matherei ◽  
D. Constantin-Teodosiu ◽  
...  

The adaptation of mitochondrial ATP production rate (MAPR) to training and detraining was evaluated in nine healthy men. Muscle samples (approximately 60 mg) were obtained before and after 6 wk of endurance training and after 3 wk of detraining. MAPR was measured in isolated mitochondria by a bioluminometric method. In addition, the activities of mitochondrial and glycolytic enzymes were determined in skeletal muscle. In response to training, MAPR increased by 70%, with a substrate combination of pyruvate + palmitoyl-L-carnitine + alpha-ketoglutarate + malate, by 50% with only pyruvate + malate, and by 92% with palmitoyl-L-carnitine + malate. With detraining MAPR decreased by 12–28% from the posttraining rate (although not significantly for all substrates). No differences were found when MAPR was related to the protein content in the mitochondrial fraction. The largest increase in mitochondrial enzyme activities induced by training was observed for cytochrome-c oxidase (78%), whereas succinate cytochrome c reductase showed only an 18% increase. The activity of citrate synthase increased by 40% and of glutamate dehydrogenase by 45%. Corresponding changes in maximal O2 uptake were a 9.6% increase by training and a 6.0% reversion after detraining. In conclusion, both MAPR and mitochondrial enzyme activities are shown to increase with endurance training and to decrease with detraining.


Genetics ◽  
1982 ◽  
Vol 102 (2) ◽  
pp. 207-221
Author(s):  
A N Wilton ◽  
C C Laurie-Ahlberg ◽  
T H Emigh ◽  
J W Curtsinger

ABSTRACT This report describes an investigation of the specificities of the genetic effects, caused by whole chromosome substitution, on the activities of 23 enzymes in Drosophila melanogaster. Two types of correlation estimates are examined, the product-moment correlation over the chromosome substitution line means and the corresponding correlation of line effects, which is a standardized covariance component estimate. The two types of correlations give very similar results. Although there is ample evidence for specific line effects on individual enzyme activities, there are extensive intercorrelations among many of the enzymes for both second- and third-chromosome substitution lines. The pattern of correlations with respect to the metabolic functions or other properties of the enzymes is difficult to visualize by inspection of the correlation matrix, so a multivariate graphical technique, the biplot (Gabriel 1971), was employed to obtain a two-dimensional view of relationships among the enzyme activities. The second and third chromosome lines show similar patterns. Four of the five mitochondrial enzymes form one highly intercorrelated group whereas another highly intercorrelated group contains several cytosolic enzymes. Within the cytosolic group, particularly high correlations are observed between enzymes that have glucose 6-phosphate as a substrate or product and between enzymes that are NADP-dependent. Although the pattern of intercorrelations is not clearly explicable in terms of metabolic relationships among the enzymes, there is some tendency for enzymes that catalyze sequential reactions or share a substrate or product to have correlated activity levels.


1993 ◽  
Vol 74 (2) ◽  
pp. 776-781 ◽  
Author(s):  
J. A. Houmard ◽  
T. Hortobagyi ◽  
P. D. Neufer ◽  
R. A. Johns ◽  
D. D. Fraser ◽  
...  

The purpose of this study was to determine whether short-term training cessation resulted in reduced GLUT-4 protein levels. Endurance- (n = 12, ET) and strength-trained (n = 12) individuals (ST) were examined before and after 14 days of training withdrawal. GLUT-4 content was determined from muscle biopsy samples of the gastrocnemius in ET and the vastus lateralis in ST. Insulin sensitivity (oral glucose tolerance test) was significantly (P < 0.05) reduced in ET and ST with training cessation. GLUT-4 content was unaltered (P > 0.05) in both groups (92 and 100% of trained values for ET and ST, respectively). In ET, citrate synthase activity decreased significantly (P < 0.05) with training withdrawal (41.0 +/- 3.6 vs. 30.6 +/- 2.8 mumol.g-1.min-1); in ST no change was evident. The decrement in insulin sensitivity with the cessation of endurance- or resistance-oriented activity is therefore not associated with a reduction in GLUT-4 protein content. Muscle oxidative capacity and GLUT-4 content do not coincide with the removal of endurance training.


2009 ◽  
Vol 297 (5) ◽  
pp. R1383-R1391 ◽  
Author(s):  
H. J. Green ◽  
E. Bombardier ◽  
M. E. Burnett ◽  
I. C. Smith ◽  
S. M. Tupling ◽  
...  

In this study, we investigated the hypothesis that the metabolic adaptations observed during steady-state exercise soon after the onset of training would be displayed during the nonsteady period of moderate exercise and would occur in the absence of increases in peak aerobic power (V̇o2peak) and in muscle oxidative potential. Nine untrained males [age = 20.8 ± 0.70 (SE) yr] performed a cycle task at 62% V̇o2peak before (Pre-T) and after (Post-T) training for 2 h/day for 5 days at task intensity. Tissue samples extracted from the vastus lateralis at 0 min (before exercise) and at 10, 60, and 180 s of exercise, indicated that at Pre-T, reductions ( P < 0.05) in phosphocreatine and increases ( P < 0.05) in creatine, inorganic phosphate, calculated free ADP, and free AMP occurred at 60 and 180 s but not at 10 s. At Post-T, the concentrations of all metabolites were blunted ( P < 0.05) at 60 s. Training also reduced ( P < 0.05) the increase in lactate and the lactate-to-pyruvate ratio observed during exercise at Pre-T. These adaptations occurred in the absence of change in V̇o2peak (47.8 ± 1.7 vs. 49.2 ± 1.7 ml·kg−1·min−1) and in the activities (mol·kg protein−1·h−1) of succinic dehydrogenase (3.48 ± 0.21 vs. 3.77 ± 0.35) and citrate synthase (7.48 ± 0.61 vs. 8.52 ± 0.65) but not cytochrome oxidase (70.8 ± 5.1 vs. 79.6 ± 6.6 U/g protein; P < 0.05). It is concluded that the tighter metabolic control observed following short-term training is initially expressed during the nonsteady state, probably as a result of increases in oxidative phosphorylation that is not dependent on changes in V̇o2peak while the role of oxidative potential remains uncertain.


2006 ◽  
Vol 31 (5) ◽  
pp. 495-501 ◽  
Author(s):  
Jason E. Tang ◽  
Joseph W. Hartman ◽  
Stuart M. Phillips

Some evidence suggests that resistance training may lower relative muscle mitochondrial content via “dilution” of the organelle in a larger muscle fibre. Such an adaptation would reduce fatigue resistance, as well as compromise oxidative ATP synthesis and the capacity for fatty-acid oxidation. We investigated the effect of resistance training on mitochondrial enzymes of the citric acid cycle (citrate synthase; CS) and β-oxidation (β-hydroxyacyl CoA dehydrogenase; β-HAD), as well as markers of the potential for glucose phosphorylation (hexokinase; HK) and glycolysis (phosphofructokinase; PFK). Twelve untrained men (21.9 ± 0.5 y; 1.79 ± 0.03 m; 83.2 ± 3.2 kg) participated in a 12 week progressive resistance-training program. Muscle biopsies were taken from the vastus lateralis before (PRE) and after (POST) training. Training increased mean muscle fibre cross-sectional area (p < 0.05) and the activities of CS (PRE = 4.53 ± 0.44 mol·kg protein–1·h–1; POST = 5.63 ± 0.40 mol·kg protein–1·h–1; p < 0.001) and β-HAD (PRE = 2.55 ± 0.28 mol·kg protein–1·h–1; POST = 3.11 ± 0.21 mol·kg protein–1·h–1; p < 0.05). The activity of HK increased 42% (p < 0.05), whereas the activity of PFK remained unchanged. We conclude that resistance training provides a stimulus for improving muscle oxidative potential, as reflected by the increased activities of CS and β-HAD following resistance training induced hypertrophy.


2000 ◽  
Vol 278 (4) ◽  
pp. E571-E579 ◽  
Author(s):  
Hervé Dubouchaud ◽  
Gail E. Butterfield ◽  
Eugene E. Wolfel ◽  
Bryan C. Bergman ◽  
George A. Brooks

To evaluate the effects of endurance training on the expression of monocarboxylate transporters (MCT) in human vastus lateralis muscle, we compared the amounts of MCT1 and MCT4 in total muscle preparations (MU) and sarcolemma-enriched (SL) and mitochondria-enriched (MI) fractions before and after training. To determine if changes in muscle lactate release and oxidation were associated with training-induced changes in MCT expression, we correlated band densities in Western blots to lactate kinetics determined in vivo. Nine weeks of leg cycle endurance training [75% peak oxygen consumption (V˙o 2 peak)] increased muscle citrate synthase activity (+75%, P < 0.05) and percentage of type I myosin heavy chain (+50%, P < 0.05); percentage of MU lactate dehydrogenase-5 (M4) isozyme decreased (−12%, P < 0.05). MCT1 was detected in SL and MI fractions, and MCT4 was localized to the SL. Muscle MCT1 contents were consistent among subjects both before and after training; in contrast, MCT4 contents showed large interindividual variations. MCT1 amounts significantly increased in MU, SL, and MI after training (+90%, +60%, and +78%, respectively), whereas SL but not MU MCT4 content increased after training (+47%, P < 0.05). Mitochondrial MCT1 content was negatively correlated to net leg lactate release at rest ( r = −0.85, P < 0.02). Sarcolemmal MCT1 and MCT4 contents correlated positively to net leg lactate release at 5 min of exercise at 65%V˙o 2 peak ( r = 0.76, P < 0.03 and r = 0.86, P < 0.01, respectively). Results support the conclusions that 1) endurance training increases expression of MCT1 in muscle because of insertion of MCT1 into both sarcolemmal and mitochondrial membranes, 2) training has variable effects on sarcolemmal MCT4, and 3) both MCT1 and MCT4 participate in the cell-cell lactate shuttle, whereas MCT1 facilitates operation of the intracellular lactate shuttle.


2010 ◽  
Vol 35 (5) ◽  
pp. 657-670 ◽  
Author(s):  
Howard J. Green ◽  
Aziz Batada ◽  
Bill Cole ◽  
Margaret E. Burnett ◽  
Helen Kollias ◽  
...  

We hypothesized that a season of ice hockey would result in extensive remodeling of muscle. Tissue sampled from the vastus lateralis of 15 players (age = 20.6 ± 0.4 years; mean ± SE) prior to (PRE) and following (POST) a season was used to characterize specific adaptations. Measurement of representative metabolic pathway enzymes indicated higher maximal activities in POST than in PRE (p < 0.05) for succinic dehydrogenase (3.26 ± 0.31 vs. 3.91 ± 0.11 mol·mg protein–1·min–1), citrate synthase (7.26 ± 0.70 vs. 8.70 ± 0.55 mol·mg protein–1·min–1), and phosphofructokinase (12.8 ± 1.3 vs. 14.4 ± 0.96 mol·mg protein–1·min–1) only. The season resulted in an increase in Na+-K+-ATPase concentration (253 ± 6.3 vs. 265 ± 6.0 pmol·g–1 wet weight), a decrease (p < 0.05) in maximal activity of the sarcoplasmic reticulum Ca2+-ATPase (107 ± 4.2 µmol·g protein–1·min–1 vs. 92.0 ± 4.6 µmol·g protein–1·min–1), and no change in the distribution (%) of fibre types. A smaller (p < 0.05) cross-sectional area (CSA) for both type I (–11.7%) and type IIA (–18.2%) fibres and a higher (p < 0.05) capillary count/CSA for type I (+17.9%) and type IIA (+17.2%) were also found over the season. No changes were found in peak oxygen consumption (51.4 ± 1.2 mL·kg–1·min–1 vs. 52.3 ± 1.3 mL·kg–1·min–1). The results suggest, based on the alterations in oxidative and perfusion potentials and muscle mass, that the dominant adaptations are in support of oxidative metabolism, which occurs at the expense of fibre CSA and possibly force-generating potential.


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