Evaluation of exercise and training on muscle lipid metabolism
Evaluation of exercise and training on muscle lipid metabolism
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DOI：
10.1152/ajpendo.1999.276.1.e106
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发表时间：
1999-01-01
影响因子：
5.1
通讯作者：
Brooks, GA
中科院分区：
文献类型：
--
作者：
Bergman, BC;Butterfield, GE;Brooks, GA
为了验证耐力训练增加肌内甘油三酯(IMTG)氧化的假说，我们在训练前[氧消耗峰值(V)的45%和65%超过点O-2峰]和训练后[训练前(V)超过点O-2峰的65%，绝对负荷(ABT)相同，训练后(V)超过点O-2峰，相同的相对强度(RLT)]的两种强度下，对训练前1h的腿部净游离脂肪酸(FFA)和甘油交换进行了研究。9名男性受试者(178.1+/-2.5 cm，81.8+/-3.3 kg，27.4+/-2.0yr)在9wk自行车训练前和训练后分别进行5次每周5次75%(V)以上的点氧-2峰负荷试验。训练前在点O-2峰上产生66.1+/-1.1%(V)的功率输出在训练后由于(V)比点O-2峰增加14.6+/-3.1%而产生54.0+/-1.7%。训练显著(P<；0.05)降低ABT时的肺呼吸交换比(RER)(训练前为0.96+/-0.01，训练后为0.93+/-0.01)，但不降低RLT(0.95+/-0.01)。训练后，无论是ABT(训练前0.98+/-0.02比训练后0.98+/-0.03)还是RLT(1.01+/-0.02)，腿部呼吸商(RQ)均无显著差异。训练后，RLT的FFA净摄取增加，而ABT的净摄取没有增加。FFA提取分数在训练后和任何运动强度下均无显著差异。从安静到运动或在ABT时，净甘油释放以及由此计算的三次甘油净释放计算的IMTG脂解没有变化，但在训练后相同的RLT下下降。肌肉活组织检查显示在运动过程中肌肉甘油三酯有轻微的变化。同时测量腿部RQ、FFA净摄取和工作腿的甘油释放表明，在腿部自行车运动中，腿部FFA氧化、FFA摄取或IMTG脂解没有变化，训练前和训练后(V)分别比DOT O-2峰值高65%和54%。训练使工作肌肉的FFA摄取增加65%(V)，而不是点O-2峰，但在所有工作强度下的高RER和RQ值表明，FFA和IMTG在中强度和大强度运动中作为燃料是次要的。
To evaluate the hypothesis that endurance training increases intramuscular triglyceride (IMTG) oxidation, we studied leg net free fatty acid (FFA) and glycerol exchange during 1 h of cycle ergometry at two intensities before training [45 and 65% of peak rate of oxygen consumption ((V) over dot O-2peak)] and after training [65% pretraining (V) over dot O-2peak, same absolute workload (ABT), and 65% posttraining (V) over dot O-2peak, Same relative intensity (RLT)]. Nine male subjects (178.1 +/- 2.5 cm, 81.8 +/- 3.3 kg, 27.4 +/- 2.0 yr) were tested before and after 9 wk of cycle ergometer training, five times per week at 75% (V) over dot O-2peak. The power output that elicited 66.1 +/- 1.1% of (V) over dot O-2peak before training elicited 54.0 +/- 1.7% after training due to a 14.6 +/- 3.1% increase in (V) over dot O-2peak. Training significantly (P < 0.05) decreased pulmonary respiratory exchange ratio (RER) values at ABT (0.96 +/- 0.01 at 65% pre- vs. 0.93 +/- 0.01 posttraining) but not RLT (0.95 +/- 0.01). After training, leg respiratory quotient (RQ) was not significantly different at either ABT (0.98 +/- 0.02 pre- vs. 0.98 +/- 0.03 posttraining) or RLT (1.01 +/- 0.02). Net FFA uptake was increased at RLT but not ABT after training. FFA fractional extraction was not significantly different after training or at any exercise intensity. Net glycerol release, and therefore IMTG lipolysis calculated from three times net glycerol release, did not change from rest to exercise or at ABT but decreased at the same RLT after training. Muscle biopsies revealed minor muscle triglyceride changes during exercise. Simultaneous measurements of leg RQ, net FFA uptake, and glycerol release by working legs indicated no change in leg FFA oxidation, FFA uptake, or IMTG lipolysis during leg cycling exercise that elicits 65% pre- and 54% posttraining (V) over dot O-2peak. Training increases working muscle FFA uptake at 65% (V) over dot O-2peak, but high RER and RQ values at all work intensities indicate that FFA and IMTG are of secondary importance as fuels in moderate and greater-intensity exercise.