The effects of exercise on skeletal and heart muscle citrate synthase and carnitine palmitoyltransferase mRNA expressions in high-calorie fed rats.

In this study, the effect of high-calorie feeding and aerobic exercise on skeletal and cardiac muscle citrate synthase (CS), carnitine palmitoyltransferase-I (CPT-I), and -II (CPT-II) mRNA expressions were evaluated. Genetically non-obese rats were grouped as normal-high calorie and sedentary-exercising. Gastrocnemius-soleus and heart muscles' CS, CPT-I, and CPT-II expressions and skeletal muscles' histopathological characteristics were evaluated. High-fat diet had increased body weight by 10% and aerobic exercise did not make any difference. Skeletal muscle CS expression was increased significantly in normal-calorie exercising group. Exercise and high-fat diet did not change CPT-I and CPT-II expressions in both heart and skeletal muscle. Histopathological evaluations demonstrated increased cytoplasmic lipid droplets in high-calorie fed sedentary rats, and exercise had reduced lipid droplets in skeletal muscle. Also, both mitochondria and nuclei distribution were impaired in high-calorie groups. In conclusion, aerobic exercise without food restriction was not enough to make significant changes in fat transportation mechanism into skeletal and heart muscle.