McKenzie Erica C, Hinchcliff Kenneth W, Valberg Stephanie J, Williamson Katherine K, Payton Mark E, Davis Michael S
Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA.
Am J Vet Res. 2008 Aug;69(8):1097-103. doi: 10.2460/ajvr.69.8.1097.
To assess changes in muscle glycogen (MG) and triglyceride (MT) concentrations in aerobically conditioned sled dogs during prolonged exercise.
54 Alaskan sled dogs fed a high-fat diet.
48 dogs ran 140-km distances on 4 consecutive days (cumulative distance, up to 560 km); 6 dogs remained as nonexercising control animals. Muscle biopsies were performed immediately after running 140, 420, or 560 km (6 dogs each) and subsequently after feeding and 7 hours of rest. Single muscle biopsies were performed during recovery at 28 hours in 7 dogs that completed 560 km and at 50 and 98 hours in 7 and 6 dogs that completed 510 km, respectively. Tissue samples were analyzed for MG and MT concentrations.
In control dogs, mean +/- SD MG and MT concentrations were 375 +/- 37 mmol/kg of dry weight (kgDW) and 25.9 +/- 10.3 mmol/kgDW, respectively. Compared with control values, MG concentration was lower after dogs completed 140 and 420 km (137 +/- 36 mmol/kgDW and 203 +/- 30 mmol/kgDW, respectively); MT concentration was lower after dogs completed 140, 420, and 560 km (7.4 +/- 5.4 mmol/kgDW; 9.6 +/- 6.9 mmol/kgDW, and 6.3 +/- 4.9 mmol/kgDW, respectively). Depletion rates during the first run exceeded rates during the final run. Replenishment rates during recovery periods were not different, regardless of distance; only MG concentration at 50 hours was significantly greater than the control value.
Concentration of MG progressively increased in sled dogs undergoing prolonged exercise as a result of attenuated depletion.
评估有氧条件下的雪橇犬在长时间运动过程中肌肉糖原（MG）和甘油三酯（MT）浓度的变化。
54只食用高脂饮食的阿拉斯加雪橇犬。
48只犬连续4天跑140公里的路程（累计距离达560公里）；6只犬作为不运动的对照动物。在跑完140、420或560公里后（每组6只犬）以及随后喂食并休息7小时后立即进行肌肉活检。分别对7只跑完560公里的犬在恢复28小时时、7只跑完510公里的犬在恢复50小时时以及6只跑完510公里的犬在恢复98小时时进行单次肌肉活检。分析组织样本中的MG和MT浓度。
在对照犬中，MG和MT浓度的平均值±标准差分别为375±37毫摩尔/千克干重（kgDW）和25.9±10.3毫摩尔/千克DW。与对照值相比，犬跑完140公里和420公里后MG浓度较低（分别为137±36毫摩尔/千克DW和203±30毫摩尔/千克DW）；犬跑完140、420和560公里后MT浓度较低（分别为7.4±5.4毫摩尔/千克DW；9.6±6.9毫摩尔/千克DW和6.3±4.9毫摩尔/千克DW）。第一次跑步期间的消耗率超过最后一次跑步期间的消耗率。恢复期间的补充率无差异，与跑步距离无关；仅50小时时的MG浓度显著高于对照值。
由于消耗减弱，长时间运动的雪橇犬的MG浓度逐渐增加。
