Brass E P, Hoppel C L, Hiatt W R
Department of Medicine, Case Western Reserve University, Cleveland.
Clin Pharmacol Ther. 1994 Jun;55(6):681-92. doi: 10.1038/clpt.1994.85.
This study was undertaken to challenge the hypothesis that short-term administration of carnitine during exercise can modify skeletal muscle carnitine homeostasis and fuel metabolism in normal humans. With a randomized, blinded, crossover design, subjects received carnitine or placebo at the start of a bicycle ergometer exercise session. During the 2 hours after intravenous administration of 185 mumol/kg carnitine, carnitine kinetics could be described with a central compartment volume of distribution of 200 ml/kg, a total clearance from this compartment of 1.9 ml/min/kg, and a renal clearance of 1.3 ml/min/kg. Carnitine administration had no effect on muscle total carnitine content or the workload-dependent accumulation of acylcarnitines in skeletal muscle. Carnitine had no effect on the respiratory exchange ratio, muscle lactate accumulation, plasma lactate concentration, muscle glycogen utilization, or plasma beta-hydroxybutyrate concentration during exercise. Thus the skeletal muscle carnitine pool is segregated from dramatic changes in the plasma carnitine pool, and short-term administration of carnitine has no significant effect on fuel metabolism during exercise in humans.
在运动期间短期给予肉碱可改变正常人体内骨骼肌肉碱的稳态及燃料代谢。采用随机、双盲、交叉设计，受试者在进行自行车测力计运动试验开始时接受肉碱或安慰剂。静脉注射185μmol/kg肉碱后的2小时内，肉碱动力学可用以下参数描述：中央室分布容积为200ml/kg，该室的总清除率为1.9ml/（min·kg），肾清除率为1.3ml/（min·kg）。给予肉碱对肌肉总肉碱含量或骨骼肌中与工作量相关的酰基肉碱积累没有影响。运动期间，肉碱对呼吸交换率、肌肉乳酸积累、血浆乳酸浓度、肌肉糖原利用或血浆β-羟基丁酸浓度均无影响。因此，骨骼肌肉碱池与血浆肉碱池的显著变化相互隔离，短期给予肉碱对人体运动期间的燃料代谢无显著影响。
