Roberts D, Smith D J, Donnelly S, Simard S
Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500 University Drive N.W., Calgary, Alberta, Canada T2N 1N4.
Clin Sci (Lond). 2000 Jan;98(1):39-45.
This study examined exercise-induced hypoxaemia (EIH) and plasma volume contraction as modulators of serum erythropoietin (Epo) production. Five athletes cycled for 3 min at supra-maximal power outputs, at each of two different elevations (1,000 m and 2,100 m). Five subjects were exposed to normobaric hypoxia (F(I)O(2)=0.159), seven subjects underwent plasmapheresis to reduce plasma volume and eight subjects were time controls for Epo levels. Oxyhaemoglobin saturation was significantly reduced during exercise and during normobaric hypoxia. The time period of haemoglobin oxygen saturation <91% was 24+/-29 s (mean+/-S.D., n=5) for exercise at 1000 m, 136+/-77 s (mean+/-S.D., n=5) for exercise at 2100 m and 178+/-255 s (mean+/-S.D., n=5) with resting hypoxic exposure. However, significantly increased serum Epo levels were observed only following exercise (24+/-3%; mean+/-S.D., n=5 at 1,000 m and 36+/-5%; mean+/-S.D., n=5 at 2,100 m). Volume contraction also resulted in increased serum Epo (35+/-6%; mean+/-S.D., n=7) in spite of a significant rise in haematocrit of 2.2%. Despite similar degrees of arterial desaturation, only the hypoxaemia induced by exercise was associated with an increase in serum Epo. This finding indicates that other factors, in addition to hypoxaemia, are important in modulating the production of Epo in response to exercise. Volume depletion in the absence of exercise resulted in increases in Epo levels that were comparable with those observed in response to exercise. The paradoxical responses of the increased haematocrit and the increase in Epo in subjects undergoing plasmapheresis suggests that plasma volume may also modulate the production of Epo.
本研究检测了运动性低氧血症（EIH）和血浆容量收缩作为血清促红细胞生成素（Epo）产生调节因子的作用。五名运动员在两种不同海拔高度（1000米和2100米）的每一个高度下，以超最大功率输出骑行3分钟。五名受试者暴露于常压低氧环境（F(I)O(2)=0.159），七名受试者接受血浆置换以减少血浆容量，八名受试者作为Epo水平的时间对照。运动期间和常压低氧期间氧合血红蛋白饱和度显著降低。血红蛋白氧饱和度<91%的时间段，在1000米处运动时为24±29秒（平均值±标准差，n=5），在2100米处运动时为136±77秒（平均值±标准差，n=5），静息低氧暴露时为178±255秒（平均值±标准差，n=5）。然而，仅在运动后观察到血清Epo水平显著升高（1000米处为24±3%；平均值±标准差，n=5；2100米处为36±5%；平均值±标准差，n=5）。尽管血细胞比容显著升高2.2%，但容量收缩也导致血清Epo升高（35±6%；平均值±标准差，n=7）。尽管动脉去饱和程度相似，但仅运动诱导的低氧血症与血清Epo升高有关。这一发现表明，除低氧血症外，其他因素在调节运动时Epo的产生中也很重要。无运动时的容量耗竭导致Epo水平升高，与运动时观察到的升高相当。血浆置换受试者血细胞比容升高和Epo升高的矛盾反应表明，血浆容量也可能调节Epo的产生。
