Hoetker David, Chung Weiliang, Zhang Deqing, Zhao Jingjing, Schmidtke Virginia K, Riggs Daniel W, Derave Wim, Bhatnagar Aruni, Bishop David, Baba Shahid P
Diabetes and Obesity Center, University of Louisville, Louisville, Kentucky.
Envirome Institute, Department of Medicine, University of Louisville, Louisville, Kentucky.
J Appl Physiol (1985). 2018 Dec 1;125(6):1767-1778. doi: 10.1152/japplphysiol.00007.2018. Epub 2018 Oct 18.
Carnosine and anserine are dipeptides synthesized from histidine and β-alanine by carnosine synthase (ATPGD1). These dipeptides, present in high concentration in the skeletal muscle, form conjugates with lipid peroxidation products such as 4-hydroxy -2-nonenal (HNE). Although skeletal muscle levels of these dipeptides could be elevated by feeding β-alanine, it is unclear how these dipeptides and their conjugates are affected by exercise training with or without β-alanine supplementation. We recruited 20 physically active men, who were allocated to either β-alanine or placebo-feeding group matched for peak oxygen consumption, lactate threshold, and maximal power. Participants completed 2 wk of a conditioning phase followed by 1 wk of exercise training, a single session of high-intensity interval training (HIIT), followed by 6 wk of HIIT. Analysis of muscle biopsies showed that the levels of carnosine and ATPGD1 expression were increased after CPET and decreased following a single session and 6 wk of HIIT. Expression of ATPGD1 and levels of carnosine were increased upon β-alanine-feeding after CPET, whereas ATPGD1 expression decreased following a single session of HIIT. The expression of fiber type markers myosin heavy chain I and IIa remained unchanged after CPET. Levels of carnosine, anserine, carnosine-HNE, carnosine-propanal, and carnosine-propanol were further increased after 9 wk of β-alanine supplementation and exercise training but remained unchanged in the placebo-fed group. These results suggest that carnosine levels and ATPGD1 expression fluctuates with different phases of training. Enhancing carnosine levels by β-alanine feeding could facilitate the detoxification of lipid peroxidation products in the human skeletal muscle. Carnosine synthase expression and carnosine levels are altered in the human skeletal muscle during different phases of training. During high-intensity interval training, β-alanine feeding promotes detoxification of lipid peroxidation products and increases anserine levels in the skeletal muscle.
肌肽和鹅肌肽是由肌肽合酶（ATPGD1）从组氨酸和β-丙氨酸合成的二肽。这些二肽在骨骼肌中含量很高，会与脂质过氧化产物如4-羟基-2-壬烯醛（HNE）形成共轭物。尽管通过喂食β-丙氨酸可以提高骨骼肌中这些二肽的水平，但尚不清楚这些二肽及其共轭物在有或没有补充β-丙氨酸的运动训练中会受到怎样的影响。我们招募了20名身体活跃的男性，将他们分配到β-丙氨酸组或安慰剂喂养组，两组在峰值耗氧量、乳酸阈值和最大功率方面相匹配。参与者先完成2周的适应阶段，然后进行1周的运动训练，单次高强度间歇训练（HIIT），随后进行6周的HIIT。肌肉活检分析表明，心肺运动试验（CPET）后肌肽水平和ATPGD1表达增加，单次训练和6周HIIT后降低。CPET后喂食β-丙氨酸会使ATPGD1表达和肌肽水平增加，而单次HIIT后ATPGD1表达降低。CPET后纤维类型标志物肌球蛋白重链I和IIa的表达保持不变。补充β-丙氨酸并进行运动训练9周后，肌肽、鹅肌肽、肌肽-HNE、肌肽-丙醛和肌肽-丙醇的水平进一步升高，但安慰剂喂养组保持不变。这些结果表明，肌肽水平和ATPGD1表达会随着训练的不同阶段而波动。通过喂食β-丙氨酸提高肌肽水平可以促进人体骨骼肌中脂质过氧化产物的解毒。在训练的不同阶段，人体骨骼肌中的肌肽合酶表达和肌肽水平会发生改变。在高强度间歇训练期间，喂食β-丙氨酸可促进脂质过氧化产物的解毒，并增加骨骼肌中鹅肌肽的水平。
