Increased activity of citrate synthase in human skeletal muscle after a single bout of prolonged exercise

Tonkonogi, Michail; Harris, B. A.; Sahlin, Kent

doi:10.1046/j.1365-201x.1997.00233.x

Cited by 48 publications

(68 citation statements)

References 5 publications

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“…Here we provide evidence that suggests that exercise has an acute effect on the training-induced increase in CS activity. These data are in agreement with human studies showing that the acute CS activity in skeletal muscle is increased after a single bout of exercise (14,27). Although different acute and chronic adaptive responses of CS activities to endurance training were found between soleus and cardiac ventricle muscles, both of the muscle types demonstrated a sim- Fig.…”

Section: Discussionsupporting

confidence: 81%

“…Although it appears clear that endurance exercise training promotes a chronic effect of CS activity elevation in skeletal muscle, results on the acute effects of endurance exercise on CS activity are less clear. Tonkonogi and co-workers (27) investigated the acute effect of a single bout of prolonged cycling on the oxidative function in human skeletal muscle. They observed that skeletal muscle CS activity was increased by 20% measured in millimoles per kilogram dry weight per minute (increased by 12% measured in related to protein content) immediately after an acute bout of exhaustive cycling in ϳ75% peak O 2 uptake.…”

Section: Discussionmentioning

confidence: 99%

“…Transient changes in skeletal muscle mitochondrial enzyme activities have been investigated after a single bout of exercise in both animals (5,9,21) and humans (14,27). Data from the human studies suggested that CS activities elevate in response to acute exercise, whereas conflicting findings in the CS activity changes after an acute bout of exercise were reported in the rat studies (5,9,12,13,26).…”

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confidence: 97%

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Citrate synthase expression and enzyme activity after endurance training in cardiac and skeletal muscles

Siu

Donley

Bryner

2003

Journal of Applied Physiology

117

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. Citrate synthase expression and enzyme activity after endurance training in cardiac and skeletal muscles. J Appl Physiol 94: 555-560, 2003; 10.1152/ japplphysiol.00821.2002.-The present study was designed to examine the acute and chronic effects of endurance treadmill training on citrate synthase (CS) gene expression and enzymatic activity in rat skeletal and cardiac muscles. Adult rats were endurance trained for 8 wk on a treadmill. They were killed 1 h (T1, n ϭ 8) or 48 h (T48, n ϭ 8) after their last bout of exercise training. Eight rats were sedentary controls (C) during the training period. CS mRNA levels and enzymatic activities of the soleus and ventricle muscles were determined. Training resulted in higher CS mRNA levels in both the soleus muscles (21% increase in T1; 18% increase in T48, P Ͻ 0.05) and ventricle muscles (23% increase in T1; 17% increase in T48, P Ͻ 0.05) when compared with the C group. The CS enzyme activities were 42 (P Ͻ 0.01) and 25% (P Ͻ 0.01) greater in the soleus muscles of T1 and T48 groups, respectively, when compared with that of the C group. Soleus CS enzyme activity was significantly greater in the T1 vs. T48 groups (P Ͻ 0.05). However, no appreciable alterations in CS enzyme activities were observed in the ventricle muscles in both training groups. These findings suggest differential responses of skeletal and cardiac muscles in CS enzymatic activity but similar responses in CS gene expression at 1 and 48 h after the last session of endurance training. Moreover, our data support the existence of an acute effect of exercise on the training-induced elevation in CS activity in rat soleus but not ventricle muscles. physical activity; oxidative enzyme; gene transcriptional expression; soleus muscle; heart muscle CITRATE SYNTHASE (CS) is one of the key regulatory enzymes in the energy-generating metabolic pathway that catalyzes the condensation of oxaloacetate and acetyl coenzyme A to form citrate in the tricarboxylic acid cycle. It has been extensively used as a metabolic marker in assessing oxidative and respiratory capacity (22). More than 30 years ago, Holloszy and his colleagues (8) reported that endurance exercise training increases the oxidative enzyme activities in skeletal muscle. After that, numerous studies were conducted to examine the effect of exercise training on muscle oxidative capacity and metabolic characteristics (7,15,20,22,29). It is generally recognized that the skeletal muscle oxidative capacity and the activities of mitochondrial enzymes are elevated by endurance exercise training.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 97%

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Citrate synthase expression and enzyme activity after endurance training in cardiac and skeletal muscles

Siu

Donley

Bryner

2003

Journal of Applied Physiology

117

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“…Modulators of COX have been identified and are thought to be an important regulatory mechanism of this enzyme complex (41,42). In addition, evidence that acute exercise increases skeletal muscle citrate synthase activity well before mRNA transcription and protein synthesis increases has been reported (43,44). Skeletal muscle citrate synthase activity did not increase after 5 h of insulin infusion in one study (45), which is consistent with the current results showing no significant insulin effect on enzyme activity after 4 h. Nevertheless, changes in allosteric activators or inhibitors of these oxidative enzymes must be considered.…”

Section: Discussionmentioning

confidence: 99%

Effect of insulin on human skeletal muscle mitochondrial ATP production, protein synthesis, and mRNA transcripts

Stump

Short

Bigelow

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

418

369

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Mitochondria are the primary site of skeletal muscle fuel metabolism and ATP production. Although insulin is a major regulator of fuel metabolism, its effect on mitochondrial ATP production is not known. Here we report increases in vastus lateralis muscle mitochondrial ATP production capacity (32-42%) in healthy humans (P < 0.01) i.v. infused with insulin (1.5 milliunits͞kg of fat-free mass per min) while clamping glucose, amino acids, glucagon, and growth hormone. Increased ATP production occurred in association with increased mRNA levels from both mitochondrial (NADH dehydrogenase subunit IV) and nuclear [cytochrome c oxidase (COX) subunit IV] genes (164 -180%) encoding mitochondrial proteins (P < 0.05). In addition, muscle mitochondrial protein synthesis, and COX and citrate synthase enzyme activities were increased by insulin (P < 0.05). Further studies demonstrated no effect of low to high insulin levels on muscle mitochondrial ATP production for people with type 2 diabetes mellitus, whereas matched nondiabetic controls increased 16 -26% (P < 0.02) when four different substrate combinations were used. In conclusion, insulin stimulates mitochondrial oxidative phosphorylation in skeletal muscle along with synthesis of gene transcripts and mitochondrial protein in human subjects. Skeletal muscle of type 2 diabetic patients has a reduced capacity to increase ATP production with high insulin levels.cytochrome c oxidase ͉ NADH dehydrogenase subunit IV ͉ amino acids ͉ citrate synthase

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“…The homogenate was then centrifuged and the supernatant was analysed for citrate synthase (CS) activity using spectrophotometric detection. 11 CS activity correlates highly with in vitro measurements of skeletal muscle mitochondrial oxidative capacity 26 and has been commonly used as a marker of muscle oxidative capacity. 27,28 Histochemical staining Serial cross-sections 10 mm thick were cut from the mounted muscle sample in a cryostat maintained at 7 20 C. The sections for fibre typing were preincubated at pH 4.30 and 4.54, and were classified as either type I, IIa or IIx according to the acid lability of different isoforms of myosin adenosine triphosphatase.…”

Section: Slow Component Of V á O 2 Kineticsmentioning

confidence: 99%

Slow component of V̇O2 kinetics: the effect of training status, fibre type, UCP3 mRNA and citrate synthase activity

et al. 2002

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OBJECTIVE:In healthy individuals performing constant-load exercise at intensities above the lactate threshold a secondary rise in pulmonary oxygen uptake (V O 2 ) occurs. V O 2 reaches a maximum and exhaustion rapidly prevails for a range of work rates lower than the maximal work rate achieved during a conventional rapid-incremental test. This phenomenon is called the slow component (SC) of V O 2 kinetics and represents an increase in V O 2 without an increase in work rate. Although still under debate, the magnitude of the SC is believed to be associated with the percentage of type II muscle fibres and their recruitment. In this study we investigated the relationship between the magnitude of the relative SC, citrate synthase activity, UCP2 and UCP3 mRNA levels and muscle fibre composition in both endurance-trained and recreationally active subjects. METHOD: The magnitude of the relative SC was measured in 12 endurance-trained (Tr) and 15 recreationally active (RA) male subjects. The magnitude of the relative SC was determined as the difference between the end-exercise V O 2 and 3 min V O 2 divided by the difference between end-exercise V O 2 and baseline V O 2 . UCP2 and UCP3 mRNA expression in the vastus lateralis was measured by RT-PCR with b-actin mRNA used as an internal control. These values were also normalized against cytochromeb mRNA to control for training induced changes in mitochondria when comparing the Tr and RA groups. Type I, IIa and IIx skeletal muscle fibre composition was determined using a routine myosin ATPase histochemical staining technique. Citrate synthase (CS) activity was measured using spectrophotometric detection. RESULTS:The magnitude of the relative SC of the Tr group had the highest correlation with citrate synthase activity (r ¼ 7 0.90, P < 0.001) and that of the RA group with V O 2 peak (r ¼ 7 0.68, P < 0.01). For the Tr group other correlations with the magnitude of the relative SC included UCP3 mRNA levels (r ¼ 0.69, P < 0.05) and the percentage of type I fibres (r ¼ 7 0.58, P < 0.05), while for the RA group they included UCP3 mRNA (r ¼ 0.58, P < 0.05) and the percentage of type IIa muscle fibres (r ¼ 0.59, P < 0.05). The Tr subjects had a lower relative SC (P ¼ 0.04) and a lower expression of UCP2 (P ¼ 0.04), and UCP3 mRNA (P ¼ 0.01) than the RA subjects. When the groups were combined the magnitude of the relative SC correlated with UCP3 mRNA (r ¼ 0.70, P < 0.01), percentage of type IIa muscle fibres (r ¼ 0.60, P < 0.01) and V O 2 peak (r ¼ 7 0.73, P < 0.01). Additionally UCP3 mRNA correlated with the percentage of type IIa muscle fibres (r ¼ 0.63, P < 0.001). CONCLUSION: Citrate synthase activity and V O 2 peak are indicators of aerobic fitness. The high negative correlations between the magnitude of the relative SC and citrate synthase activity and V O 2 peak, of the Tr and RA subjects, respectively, suggests that the magnitude of the relative SC is inversely correlated with aerobic fitness. Additionally the correlations between UCP3 mRNA and the magnitude of the relative SC...

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Increased activity of citrate synthase in human skeletal muscle after a single bout of prolonged exercise

Cited by 48 publications

References 5 publications

Citrate synthase expression and enzyme activity after endurance training in cardiac and skeletal muscles

Citrate synthase expression and enzyme activity after endurance training in cardiac and skeletal muscles

Effect of insulin on human skeletal muscle mitochondrial ATP production, protein synthesis, and mRNA transcripts

Slow component of V̇O2 kinetics: the effect of training status, fibre type, UCP3 mRNA and citrate synthase activity

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