Biljanović-Paunović L, Clemons G K, Ivanović Z, Pavlović-Kentera V
Institute for Medical Research, Belgrade, Yugoslavia.
Indian J Med Res. 1996 Nov;104:304-10.
In order to better understand the mechanisms affecting erythropoietin (Epo) synthesis and red cell mass increase under chronic hypoxia, we examined Epo production and erythroid progenitors (CFU-E) in rats exposed to normobaric hypoxia for four weeks. Hypoxia induced the rise of hematocrit (Htc), hemoglobin (Hb) concentration and the red blood cell (RBC) number with a plateau in hematocrit values after two weeks. After 24 h of hypoxia, Epo levels were increased 20 fold, followed by a significant decrease. After the first week of hypoxia, the values were still higher than in the controls, but after two weeks Epo levels did not differ significantly from the normal values. The fall of Epo levels coincided with the plateau values of hematocrit. The changes in the CFU-E number followed the changes in Epo concentration: a two fold increase after 24 h of hypoxia; a further increase during the next two weeks reaching a peak on day 14, and then a progressive decrease at the time when Epo concentration was at a normal level. Although decreased, but still higher than normal, the CFU-E number during the last two weeks of hypoxia could be necessary for the maintenance of an achieved steady state under persistent hypoxic conditions with normal Epo concentration sufficient to maintain the existing rate of erythropoiesis.
为了更好地理解慢性缺氧状态下影响促红细胞生成素（Epo）合成及红细胞量增加的机制，我们检测了常压缺氧4周大鼠的Epo生成情况及红系祖细胞（CFU-E）。缺氧导致血细胞比容（Htc）、血红蛋白（Hb）浓度及红细胞（RBC）数量升高，2周后血细胞比容值趋于平稳。缺氧24小时后，Epo水平升高20倍，随后显著下降。缺氧第1周后，其值仍高于对照组，但2周后Epo水平与正常组无显著差异。Epo水平的下降与血细胞比容的平稳值一致。CFU-E数量的变化与Epo浓度的变化一致：缺氧24小时后增加2倍；在接下来的2周内进一步增加，在第14天达到峰值，然后在Epo浓度恢复正常水平时逐渐下降。尽管缺氧最后2周CFU-E数量减少，但仍高于正常水平，这对于在持续缺氧条件下维持已达到的稳态可能是必要的，此时正常的Epo浓度足以维持现有的红细胞生成速率。
