Friedlander A L, Casazza G A, Horning M A, Buddinger T F, Brooks G A
Exercise Physiology Laboratory, Department of Integrative Biology, University of California, Berkeley, California 94720-3140, USA.
Am J Physiol. 1998 Nov;275(5):E853-63. doi: 10.1152/ajpendo.1998.275.5.E853.
We examined the effects of exercise intensity and training [12 wk, 5 days/wk, 1 h, 75% peak oxygen consumption (VO2 peak)] on lipolysis and plasma free fatty acid (FFA) flux in women (n = 8; 24.3 +/- 1.6 yr). Two pretraining trials (45 and 65% of VO2 peak) and two posttraining trials [same absolute workload (65% of old VO2 peak; ABT) and same relative workload (65% of new VO2 peak; RLT)] were performed using infusions of [1,1,2,3,3-2H]glycerol and [1-13C]palmitate. Pretraining rates of FFA appearance (Ra), disappearance (Rd), and oxidation (Rox p) were similar between the 65% (6.8 +/- 0.6, 6.2 +/- 0.7, 3.1 +/- 0.3 micromol. kg-1. min-1, respectively) and the 45% of VO2 peak trials. At ABT and RLT training increased FFA Ra to 8.4 +/- 1.0 and 9.7 +/- 1.1 micromol. kg-1. min-1, Rd to 8.3 +/- 1.0 and 9.5 +/- 1.1 micromol. kg-1. min-1, and Rox p to 4.8 +/- 0.4 and 6.7 +/- 0.7 micromol. kg-1. min-1, respectively (P </= 0.05). Total FFA oxidation from respiratory exchange ratio was also elevated after training at ABT and RLT, with all of the increase attributed to plasma FFA sources. Pretraining, glycerol Ra was higher during exercise at 65 than 45% of VO2 peak (6. 9 +/- 0.9 vs. 4.7 +/- 0.6 micromol. kg-1. min-1) but was not changed by training. In young women 1) plasma FFA kinetics and oxidation are not linearly related to exercise intensity before training, 2) training increases FFA Ra, Rd, and Rox p whether measured at given absolute or relative exercise intensities, 3) whole body lipolysis (glycerol Ra) during exercise is not significantly impacted by training, and 4) training-induced increases in plasma FFA oxidation are the main contributor to elevated total FFA oxidation during exercise exertion after training.
我们研究了运动强度和训练[12周，每周5天，每次1小时，75%最大摄氧量（VO₂峰值）]对女性（n = 8；24.3±1.6岁）脂肪分解和血浆游离脂肪酸（FFA）通量的影响。使用[1,1,2,3,3-²H]甘油和[1-¹³C]棕榈酸酯输注进行了两次训练前试验（VO₂峰值的45%和65%）以及两次训练后试验[相同的绝对工作量（旧VO₂峰值的65%；ABT）和相同的相对工作量（新VO₂峰值的65%；RLT）]。在VO₂峰值的65%（分别为6.8±0.6、6.2±0.7、3.1±0.3微摩尔·千克⁻¹·分钟⁻¹）和45%的试验中，训练前FFA的出现率（Ra）、消失率（Rd）和氧化率（Rox p）相似。在ABT和RLT时，训练使FFA的Ra分别增加到8.4±1.0和9.7±1.1微摩尔·千克⁻¹·分钟⁻¹，Rd分别增加到8.3±1.0和9.5±1.1微摩尔·千克⁻¹·分钟⁻¹，Rox p分别增加到4.8±0.4和6.7±0.7微摩尔·千克⁻¹·分钟⁻¹（P≤0.05）。在ABT和RLT训练后，通过呼吸交换率计算的总FFA氧化也升高，所有增加均归因于血浆FFA来源。训练前，在VO₂峰值的65%运动期间甘油的Ra高于45%（6.9±0.9对4.7±0.6微摩尔·千克⁻¹·分钟⁻¹），但训练后未改变。在年轻女性中，1）训练前血浆FFA动力学和氧化与运动强度并非线性相关；2）无论在给定的绝对或相对运动强度下测量，训练均会增加FFA的Ra、Rd和Rox p；3）运动期间全身脂肪分解（甘油Ra）不受训练的显著影响；4）训练引起的血浆FFA氧化增加是训练后运动期间总FFA氧化升高的主要原因。
