Lenz T, Nadansky M, Gossmann J, Oremek G, Geiger H
Division of Nephrology, Medical Clinic IV, Johann Wolfgang Goethe University, Frankfurt am Main, Germany.
Am J Hypertens. 1998 Aug;11(8 Pt 1):1028-31. doi: 10.1016/s0895-7061(98)00086-7.
Chronic hypoxia has been shown to increase plasma endothelin levels. The current study was undertaken to examine the effect of exercise-induced tissue hypoxia on plasma levels of endothelin-1 (ET-1) and its precursor big endothelin-1 (Big-ET-1). After approval by the local ethical committee an incremental dynamic exercise test was performed in 12 physically trained volunteers (aged 20 to 40 years), using an electrically braked bicycle ergometer. The protocol included a step-wise increase of the workload until a heart rate of 130/min was reached, followed by a maintenance period of 25 min, and a further step-wise increase until exhaustion. Blood was drawn before, at several time points during, and 5 min after termination of the study for determination of ET-1, Big-ET-1, plasma renin activity (PRA), angiotensin converting enzyme (ACE), norepinephrine, epinephrine, and lactate. Lactate levels at baseline were 14.5 +/- 1.6 mg/dL (mean +/- SEM), which increased to 76.5 +/- 4.8 mg/dL at the time of exhaustion (P < .01). Baseline values for ET-1 and Big-ET-1 were 0.264 +/- 0.061 and 0.637 +/- 0.130 fmol/ml, respectively, which remained essentially unaltered throughout the exercise test. PRA was 1.46 +/- 0.45 ng/mL/h before exercise and increased to 3.55 +/- 0.96 ng/mL/h at exhaustion (P < .001). Norepinephrine and epinephrine were also increased at exhaustion. The study demonstrates that exhaustive physical exercise with acute development of pronounced tissue hypoxia--in contrast to chronic hypoxia--does not influence the release of ET-1 or Big-ET-1 or the conversion of the precursor to the active compound. Unlike endothelin, circulating renin and the catecholamines were markedly stimulated by this maneuver.
慢性缺氧已被证明会增加血浆内皮素水平。本研究旨在探讨运动诱导的组织缺氧对血浆内皮素-1（ET-1）及其前体大内皮素-1（Big-ET-1）水平的影响。经当地伦理委员会批准，对12名身体受过训练的志愿者（年龄20至40岁）进行递增动态运动试验，使用电动刹车自行车测力计。试验方案包括逐步增加工作量，直至心率达到130次/分钟，随后维持25分钟，然后进一步逐步增加直至力竭。在研究开始前、过程中的几个时间点以及结束后5分钟采集血液，以测定ET-1、Big-ET-1、血浆肾素活性（PRA）、血管紧张素转换酶（ACE）、去甲肾上腺素、肾上腺素和乳酸。基线乳酸水平为14.5±1.6mg/dL（平均值±标准误），在力竭时升至76.5±4.8mg/dL（P<.01）。ET-1和Big-ET-1的基线值分别为0.264±0.061和0.637±0.130fmol/ml，在整个运动试验过程中基本保持不变。运动前PRA为1.46±0.45ng/mL/h，力竭时升至3.55±0.96ng/mL/h（P<.001）。力竭时去甲肾上腺素和肾上腺素也升高。该研究表明，与慢性缺氧相反，导致明显组织缺氧急性发展的力竭性体育锻炼不会影响ET-1或Big-ET-1的释放，也不会影响前体向活性化合物的转化。与内皮素不同，这种操作可显著刺激循环肾素和儿茶酚胺。
