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

Abstract

. 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.

Lipotoxicity: the obese and endurance-trained paradox

“…10,11 Additionally, ETr, unlike obesity, also results in an increase in CPT-I, citrate synthase and cytochrome c oxidase gene expression and their respective enzyme activities. [12][13][14][15][16][17] Therefore, the mechanisms regulating IMTG storage in ETr subjects appear to differ to those from obese subjects. Endurance exercise has been shown to use both carbohydrate and lipids as a fuel source.…”

Acute cold and exercise training upregulate similar aspects of fatty acid transport and catabolism in house sparrows, Passer domesticus

“…The effects of a variety of exercise training protocols on skeletal muscle HOAD and CS activities/levels have been intensively studied. HOAD (Tremblay et al, 1994;Burgomaster et al, 2008) and CS (Siu et al, 2003;Talanian et al, 2007) activities generally increase with exercise training or cold exposure in birds and mammals, although a few studies documented stable HOAD (Burgomaster et al, 2006) or CS (Price et al, 2010) activities with exercise training. For free-living birds, studies have also documented either increased (Guglielmo et al, 2002;McFarlan et al, 2009) or stable (Liknes and Swanson, 2011) HOAD activity with both migration and winter acclimatization in birds.…”

The effect of intermittent cryotherapy on the activities of citrate synthase and lactate dehydrogenase in regenerating skeletal muscle

“…Therefore, LDH/CS activity ratio presents low levels in the muscles with high oxidative capacity, while high levels are found in the muscles with low oxidative capacity (Driedzic and Almeida-Val 1996). The recovery of metabolic pathways following the muscle injury and its relationship with physical therapy intervention, such as cryotherapy, remains to be investigated (Tonkonogi et al 1997;Siu et al 2003). Merrick et al (1999) showed that the application of cryotherapy for five hours after crushing injury reduced the injured area of sural triceps of the rats.…”