Tang F-C, Chan C-C
Graduate Institute of Nutritional Sciences and Education, Department of Human Development and Family Studies, National Taiwan Normal University, Taipei, Taiwan.
Department of Physical Education, National Taiwan Normal University, Taipei, Taiwan.
Eur J Clin Nutr. 2017 May;71(5):587-593. doi: 10.1038/ejcn.2016.161. Epub 2016 Sep 28.
BACKGROUND/OBJECTIVES: Branched-chain amino acids (BCAAs) and purine nucleotide cycle (PNC) are both associated with energy metabolism. The purpose of this study was to explore the influences of BCAA supplementation on the PNC activity of male athletes in response to a bout of endurance running exercise.
SUBJECTS/METHODS: Twelve male athletes (20.3±1.4 years) participated in the study. Each of the athletes received 12 g of a BCAA supplement (leucine 54%, isoleucine 19% and valine 27%) per day during the study. They performed two identical 60-min running exercises (65-70% maximum heart rate reserved) before and after receiving the BCAA supplements for 15 days. In addition to body composition measurement, plasma and urinary samples were also collected. Plasma samples were examined for the concentrations of glucose, lactate, BCAAs, alanine, glutamine, aspartate, hypoxanthine and uric acid. Urinary samples were examined for the concentrations of urea nitrogen, hydroxyproline, 3-methylhistidine and creatinine.
Body composition and the concentrations of urinary metabolites were not affected by BCAA supplementation, whereas clearance of plasma lactate after recovery from exercise was enhanced by BCAA supplementation (P<0.05). Plasma aspartate concentration was increased (P<0.05), whereas plasma glutamine, hypoxanthine and uric acid concentrations were decreased (P<0.05) by BCAA supplementation.
The findings suggest that BCAA supplements not only provided additional substrate to meet the energy demands of the athletes during endurance exercise but also reduced their PNC activity, and subsequently decreased uric acid production and reduced the incidence of gout in a person engaging in endurance exercise.
背景/目的：支链氨基酸（BCAAs）和嘌呤核苷酸循环（PNC）均与能量代谢相关。本研究旨在探讨补充BCAAs对男性运动员在一次耐力跑运动后PNC活性的影响。
受试者/方法：12名男性运动员（20.3±1.4岁）参与了本研究。在研究期间，每位运动员每天服用12克BCAA补充剂（亮氨酸54%、异亮氨酸19%和缬氨酸27%）。他们在接受BCAA补充剂15天前后进行了两次相同的60分钟跑步运动（保留最大心率的65 - 70%）。除了测量身体成分外，还采集了血浆和尿液样本。检测血浆样本中葡萄糖、乳酸、BCAAs、丙氨酸、谷氨酰胺、天冬氨酸、次黄嘌呤和尿酸的浓度。检测尿液样本中尿素氮、羟脯氨酸、3 - 甲基组氨酸和肌酐的浓度。
补充BCAAs对身体成分和尿液代谢物浓度没有影响，而补充BCAAs可提高运动恢复后血浆乳酸的清除率（P<0.05）。补充BCAAs可使血浆天冬氨酸浓度升高（P<0.05），而血浆谷氨酰胺、次黄嘌呤和尿酸浓度降低（P<0.05）。
研究结果表明，BCAA补充剂不仅在耐力运动期间为运动员提供了额外的底物以满足能量需求，还降低了他们的PNC活性，随后减少了尿酸生成，并降低了耐力运动者痛风的发病率。
