Department of Athletics Strength and Conditioning, Poznan University of Physical Education, Poznań, Poland.
Department of Inorganic and Analytical Chemistry, Poznan University of Medical Sciences, Poznań, Poland.
PLoS One. 2024 Aug 30;19(8):e0309529. doi: 10.1371/journal.pone.0309529. eCollection 2024.
Circulating blood is an important plasma free amino acids (PFAAs) reservoir and a pivotal link between metabolic pathways. No comparisons are available between athletes with opposite training adaptations that include a broader spectrum of both proteinogenic and non-proteinogenic amino acids, and that take into account skeletal muscle mass. We hypothesized that the levels of the exercise-induced PFAAs concentration are related to the type of training-related metabolic adaptation. We compared highly trained endurance athletes (n = 11) and sprinters (n = 10) aged 20‒35 years who performed incremental exercise until exhaustion. Venous blood was collected before and during the test and 30-min recovery (12 samples). Forty-two PFAAs were assayed using LC-ESI-MS/MS technique. Skeletal muscle mass was estimated using dual X-ray absorptiometry method. Glutamine and alanine were dominant PFAAs throughout the whole exercise and recovery period (~350‒650 μmol∙L-1). Total, combined proteinogenic, non-essential, and non-proteinogenic PFAAs levels were significantly higher in endurance athletes than sprinters (ANOVA group effects: p = 0.007, η2 = 0.321; p = 0.011, η2 = 0.294; p = 0.003, η2 = 0.376; p = 0.001, η2 = 0.471, respectively). The exercise response was more pronounced in endurance athletes, especially for non-proteinogenic PFAAs (ANOVA interaction effect: p = 0.038, η2 = 0.123). Significant between-group differences were observed for 19 of 33 PFAAs detected, including 4 essential, 7 non-essential, and 8 non-proteinogenic ones. We demonstrated that the PFAAs response to incremental aerobic exercise is associated with the type of training-related metabolic adaptation. A greater turnover and availability of circulating PFAAs for skeletal muscles and other body tissues is observed in endurance- than in sprint-trained individuals. Non-proteinogenic PFAAs, despite low concentrations, also respond to exercise loads, indicating their important, though less understood role in exercise metabolism. Our study provides additional insight into the exercise-induced physiological response of PFAAs, and may also provide a rationale in discussions regarding dietary amino acid requirements in high-performance athletes with respect to sports specialization.
循环血液是血浆游离氨基酸（PFAAs）的重要储存库，也是代谢途径之间的关键联系。目前还没有比较两种截然相反的训练适应性的运动员之间的 PFAAs 水平，这些适应性包括更广泛的蛋白源和非蛋白源氨基酸，并且考虑到骨骼肌质量。我们假设运动引起的 PFAAs 浓度与训练相关的代谢适应类型有关。我们比较了年龄在 20-35 岁之间的 11 名高训练耐力运动员和 10 名短跑运动员，他们进行了递增运动直至力竭。在测试前和测试期间以及 30 分钟恢复期间采集静脉血（12 个样本）。使用 LC-ESI-MS/MS 技术测定 42 种 PFAAs。使用双 X 射线吸收法估计骨骼肌质量。谷氨酰胺和丙氨酸是整个运动和恢复期间（~350-650μmol·L-1）的主要 PFAAs。耐力运动员的总、组合蛋白源、非必需和非蛋白源 PFAAs 水平明显高于短跑运动员（方差分析组效应：p=0.007，η2=0.321；p=0.011，η2=0.294；p=0.003，η2=0.376；p=0.001，η2=0.471）。耐力运动员的运动反应更为明显，特别是对于非蛋白源 PFAAs（方差分析交互效应：p=0.038，η2=0.123）。在检测到的 33 种 PFAAs 中有 19 种观察到组间差异显著，包括 4 种必需、7 种非必需和 8 种非蛋白源。我们证明，递增有氧运动对 PFAAs 的反应与训练相关的代谢适应类型有关。在耐力训练个体中，循环 PFAAs 对骨骼肌和其他身体组织的周转率和可用性更高。尽管浓度较低，但非蛋白源 PFAAs 也对运动负荷作出反应，表明它们在运动代谢中具有重要但尚未被充分了解的作用。我们的研究为 PFAAs 运动引起的生理反应提供了更多的见解，并可能为关于具有运动专业化的高性能运动员的饮食氨基酸需求的讨论提供依据。
