Tsuchiya Yoshifumi, Ando Daisuke, Goto Kazushige, Kiuchi Masataka, Yamakita Mitsuya, Koyama Katsuhiro
Graduate School of Sport and Health Science, Ritsumeikan University.
Tohoku J Exp Med. 2014 Jun;233(2):135-40. doi: 10.1620/tjem.233.135.
Irisin is mainly released from skeletal muscle (myocytes) and promotes thermogenesis by browning of the white adipose tissue. Although exercise has been shown to increase irisin concentration in blood and myocytes via up-regulation peroxisome proliferator receptor γ coactivator-1α (PGC-1α) expression, the influence of exercise intensity on irisin secretion remains unclear. Therefore, we determined circulating irisin responses following a single bout of running at different intensities. Six sedentary males underwent treadmill running under two different conditions: a low-intensity (40% of VO2max) exercise trial (LIE) or a high-intensity (80% of VO2max) exercise trial (HIE). The exercises in LIE and HIE were lasted for 20 and 40 min, respectively. All subjects underwent the two trials on separate days, and a randomized cross-over design was used. Blood samples were collected before (Pre) and immediately after exercise, at 3, 6, and 19 h after exercise. Energy consumption during exercise did not significantly differ between the two trials. HIE significantly increased blood lactate and serum lactate dehydrogenase levels (P < 0.05). Compared with pre-exercise levels, the irisin concentrations were elevated at 6 h (18% increase) and 19 h (23% increase) after HIE, but significantly decreased after LIE. The relative irisin concentrations (compared with pre-exercise levels) were significantly greater in HIE than in LIE immediately after exercise, and at 6 and 19 h after exercise (P < 0.05). These findings suggest that irisin secretion after acute running exercise is affected by exercise intensity, independent of energy consumption.
鸢尾素主要从骨骼肌（肌细胞）释放，并通过白色脂肪组织的褐色化促进产热。尽管已有研究表明运动可通过上调过氧化物酶体增殖物激活受体γ共激活因子-1α（PGC-1α）的表达来增加血液和肌细胞中鸢尾素的浓度，但运动强度对鸢尾素分泌的影响仍不清楚。因此，我们测定了在不同强度单次跑步后循环鸢尾素的反应。六名久坐不动的男性在两种不同条件下进行跑步机跑步：低强度（最大摄氧量的40%）运动试验（LIE）或高强度（最大摄氧量的80%）运动试验（HIE）。LIE和HIE中的运动分别持续20分钟和40分钟。所有受试者在不同日期进行这两项试验，并采用随机交叉设计。在运动前（Pre）、运动后即刻、运动后3小时、6小时和19小时采集血样。两项试验中运动期间的能量消耗没有显著差异。HIE显著增加了血乳酸和血清乳酸脱氢酶水平（P<0.05）。与运动前水平相比，鸢尾素浓度在HIE后6小时（增加18%）和19小时（增加23%）升高，但在LIE后显著降低。运动后即刻、运动后6小时和19小时，HIE中鸢尾素的相对浓度（与运动前水平相比）显著高于LIE（P<0.05）。这些发现表明，急性跑步运动后鸢尾素的分泌受运动强度影响，与能量消耗无关。
