Morales Flor E, Forsse Jeffrey S, Andre Thomas L, McKinley-Barnard Sarah K, Hwang Paul S, Anthony Ian G, Tinsley Grant M, Spillane Mike, Grandjean Peter W, Ramirez Alejandro, Willoughby Darryn S
a Department of Health , Human Performance and Recreation, Baylor University , Waco , Texas.
b Department of Health , Kinesiology and Sport, University of South Alabama , Mobile , Alabama.
J Am Coll Nutr. 2017 Mar-Apr;36(3):200-209. doi: 10.1080/07315724.2016.1256240. Epub 2017 Mar 20.
β-Aminoisobutyric acid (BAIBA) has shown to modulate uncoupling protein (UCP)-1 expression, which is mainly expressed in white adipose tissue; however, no studies to date have analyzed its potential effect on the main uncoupling protein of skeletal muscle, UCP-3. The main goal of this study was to assess the potential effect of acute aerobic exercise on serum BAIBA and skeletal muscle UCP-3. The secondary goal was to assess the potential involvement of the transcription factors proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and peroxisome proliferator-activated receptor alpha (PPARα), as well as free fatty acids (FFAs) in UCP-3 expression. A tertiary goal of the study was to evaluate the potential effect of consuming a preexercise meal on the outcome of the first 2 objectives.
In a randomized crossover design, untrained participants performed 2 acute cycling sessions (350 kcal at 70% of their VO) after 2 experimental conditions: (1) consumption of a multi-macronutrient shake and (2) a fasting period of 8 hours. Blood samples were taken at baseline, preexercise, postexercise, 1 hour, and 4 hours postexercise, and muscle biopsies were taken at the last 4 time points. UCP-3 protein concentration and expression, as well as the mRNA expression of PGC-1α and PPARα, were measured in muscle, and BAIBA, glucose, and FFA were measured in serum.
Aerobic exercise failed to induce a significant effect on serum BAIBA, PGC-1α, and PPARα regardless on the feeding condition. Despite the lack of effect of exercise on the previous variables, UCP-3 expression and protein concentration significantly increased in the shake condition.
The expression of human skeletal muscle UCP-3 as a result of exercise might be controlled by factors other than BAIBA.
β-氨基异丁酸（BAIBA）已被证明可调节解偶联蛋白（UCP）-1的表达，UCP-1主要在白色脂肪组织中表达；然而，迄今为止尚无研究分析其对骨骼肌主要解偶联蛋白UCP-3的潜在影响。本研究的主要目的是评估急性有氧运动对血清BAIBA和骨骼肌UCP-3的潜在影响。次要目的是评估转录因子增殖激活受体γ共激活因子1α（PGC-1α）和过氧化物酶体增殖物激活受体α（PPARα）以及游离脂肪酸（FFA）在UCP-3表达中的潜在作用。本研究的第三个目的是评估运动前进餐对前两个目标结果的潜在影响。
在随机交叉设计中，未经训练的参与者在两种实验条件下进行了2次急性骑行训练（以70%的最大摄氧量消耗350千卡热量）：（1）饮用含多种宏量营养素的奶昔；（2）禁食8小时。在基线、运动前、运动后、运动后1小时和4小时采集血样，并在最后4个时间点采集肌肉活检样本。测量肌肉中UCP-3蛋白浓度和表达以及PGC-1α和PPARα的mRNA表达，并测量血清中的BAIBA、葡萄糖和FFA。
无论进食情况如何，有氧运动均未对血清BAIBA、PGC-1α和PPARα产生显著影响。尽管运动对上述变量没有影响，但在饮用奶昔的情况下，UCP-3表达和蛋白浓度显著增加。
运动导致的人类骨骼肌UCP-3表达可能受BAIBA以外的因素控制。
