Dyck D J, Bonen A
Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Am J Physiol. 1998 Nov;275(5):E888-96. doi: 10.1152/ajpendo.1998.275.5.E888.
We examined the oxidation and esterification of palmitate and the hydrolysis and oxidation of intramuscular lipids in isolated soleus muscles at rest and during tetanic contractions (2-40 tetani/min). Muscles were pulsed with [14C]palmitate to prelabel all intramuscular lipid pools. Muscles remained at rest or were then stimulated to contract at 2, 8, 20, or 40 tetani/min (30 min) in the presence of [3H]palmitate. Palmitate oxidation was increased 412% at 2 tetani/min (P < 0.05) and 880% at 8 tetani/min (P < 0.05). During contraction there was an absolute increase in esterification of palmitate to triacylglycerol in proportion with the increasing rate of palmitate oxidation. Intramuscular lipid oxidation provided approximately 77% of the total muscle energy compared with approximately 3% provided by exogenous palmitate under all conditions, with carbohydrate sources (glycogen and glucose) providing approximately 20% of the total energy. Thus, during muscle contraction, the oxidation rates of both exogenous and intramuscular lipids are increased in proportion to each other, while concomitantly palmitate is esterified in proportion to its oxidation.
我们研究了离体比目鱼肌在静息状态以及强直收缩（2 - 40次强直收缩/分钟）期间棕榈酸的氧化和酯化过程，以及肌内脂质的水解和氧化过程。向肌肉中注入[14C]棕榈酸以预标记所有肌内脂质池。肌肉保持静息状态，或随后在[3H]棕榈酸存在的情况下，分别以2、8、20或40次强直收缩/分钟的频率刺激收缩30分钟。棕榈酸氧化在2次强直收缩/分钟时增加了412%（P < 0.05），在8次强直收缩/分钟时增加了880%（P < 0.05）。在收缩过程中，棕榈酸酯化生成三酰甘油的量绝对增加，且与棕榈酸氧化速率的增加成比例。在所有条件下，肌内脂质氧化提供了约77%的肌肉总能量，相比之下，外源性棕榈酸提供约3%的能量，碳水化合物来源（糖原和葡萄糖）提供约20%的总能量。因此，在肌肉收缩期间，外源性和肌内脂质的氧化速率相互成比例增加，同时棕榈酸酯化与其氧化成比例。
