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Effects of Training on Acetyl CoA Carboxylase in the Heart and Its Role in Cardioprotection

出版	University of Wyoming, 2011
ISBN	12671445999781267144591
URL	http://books.google.com.hk/books?id=vTxrAQAACAAJ&hl=&source=gbs_api

註釋This study investigated the effects of 12 weeks of endurance exercise training in adult male C57BL/6 mice on cardiac phosphorylated acetyl-CoA carboxylase (pACC) activity in response to the acute metabolic stress imposed by a single bout of exhaustive exercise. Purpose. The purpose of this study was to investigate how exercise training influences pACC levels measured in a state of exercise-induced exhaustion, and whether or not this response differs from that seen in sedentary subjects exposed to the same exhaustive exercise stress. Methods. Twenty-five adult (15-18 weeks) male C57BL/6 mice were randomly assigned to one of three groups: (1) Sedentary-Resting Controls (n=5); these animals were acclimated to handling for ten days prior to sacrifice and killed in a resting state. (2) Sedentary-Exhausted (n=10); these animals were acclimated to treadmill walking at slow speeds (less than 10 m/min, 10 min/day) for one week prior to sacrifice, and were sacrificed in an exhausted state. (3) Trained- Exhausted (n=10); these animals were exposed to 12 weeks of endurance exercise training on motor driven treadmill 6 days/wk, up to 1 hr./day at progressively increasing speeds on a 25° incline. They were sacrificed in an exhausted state. At the end of the 12 week training protocol both the trained- and sedentary-exhausted groups were ramp-test exercised to the point of exhaustion. Immediately post-exercise, left ventricular (LV) tissue from both groups was rapidly excised, freeze-clamped, homogenized, and proteins extracted for immunoblotting analysis. LV tissue was also obtained from sedentary-resting controls. Heart and body weights of all animals were recorded as well. Results. Maximal running velocity was significantly higher in the trained exhausted group (43.8 plus or minus 0.70 m/min) compared to the sedentary exhausted group (33.8 plus or minus 1 m/min, P less than 0.01). Heart weight to body weight ratio within the trained exhausted group was also found to be significantly greater (5.2 plus or minus .20 mg/g) when compared to both the sedentary resting (4.10 plus or minus .13 mg/g) and the sedentary exhausted groups (4.43 plus or minus .26 mg/g, P less than 0.05). Cardiac pACC activity was not found to be significantly different between any of the three groups. However, the same analysis did reveal a trend (P less than 0.078) towards an overall difference. Conclusions. Training did not result in a significant increase in pACC activity, however based on the trends towards an increase observed it is possible that an upregulation in beta-oxidation occurred resulting in conferred cardioprotection. These findings demonstrate that training could potentially increase phosphorylation of ACC during exhaustive exercise and ultimately lead to an increase in fatty acid oxidation under these conditions.