Connes Philippe, Caillaud Corinne, Mercier Jacques, Bouix Didier, Casties Jean François
Faculté des Sciences du Sport et de l'Education Physique, F-34090 Montpellier, France.
J Appl Physiol (1985). 2004 Jul;97(1):326-32. doi: 10.1152/japplphysiol.00715.2003. Epub 2004 Feb 13.
Previous studies showed that erythropoietin not only increases erythrocyte production but is also essential in both the synthesis and the good functioning of several erythrocyte membrane proteins, including band 3. It is still unknown whether anion and/or H(+) fluxes are modified by erythropoietin. This study aimed to evaluate the effect of recombinant human erythropoietin (rHuEPO) injections on lactate transport into erythrocytes via band 3 and H(+)-monocarboxylate transporter MCT-1, two proteins involved in lactate exchange. Nine athletes received subcutaneous rHuEPO (50 U/kg body mass 3 times a week for 4 wk), and seven athletes received a saline solution (placebo group). All subjects were also supplemented with oral iron and vitamins B(9) and B(12). Lactate transport into erythrocytes was studied before and after the rHuEPO treatment at different lactate concentrations (1.6, 8.1, 41, and 81.1 mM). After treatment, MCT-1 lactate uptake was increased at 1.6, 41 (P < 0.01), and 81.1 mM lactate concentration (P < 0.001) although lactate uptake via band 3 and nonionic diffusion were unchanged. MCT-1 maximal velocity increased in the rHuEPO group (P < 0.05), reaching higher values than in the placebo group (P < 0.05) after treatment. Our results show that rHuEPO injections increased MCT-1 lactate influx at low and high lactate concentrations. The increase in MCT-1 maximal velocity suggests that rHuEPO may stimulate MCT-1 synthesis during erythrocyte formation in bone marrow.
先前的研究表明，促红细胞生成素不仅能增加红细胞生成，而且对包括带3蛋白在内的多种红细胞膜蛋白的合成及正常功能发挥也至关重要。促红细胞生成素是否会改变阴离子和/或H⁺通量仍不清楚。本研究旨在评估重组人促红细胞生成素（rHuEPO）注射对乳酸通过带3蛋白和H⁺-单羧酸转运体MCT-1进入红细胞的影响，这两种蛋白参与乳酸交换。9名运动员接受皮下注射rHuEPO（50 U/kg体重，每周3次，共4周），7名运动员接受生理盐水注射（安慰剂组）。所有受试者还口服补充铁以及维生素B₉和B₁₂。在不同乳酸浓度（1.6、8.1、41和81.1 mM）下，研究了rHuEPO治疗前后乳酸进入红细胞的情况。治疗后，在乳酸浓度为1.6、41（P<0.01）和81.1 mM（P<0.001）时，MCT-1对乳酸的摄取增加，尽管通过带3蛋白的乳酸摄取和非离子扩散未发生变化。rHuEPO组MCT-1的最大速度增加（P<0.05），治疗后达到的值高于安慰剂组（P<0.05）。我们的结果表明，rHuEPO注射在低乳酸浓度和高乳酸浓度下均增加了MCT-1对乳酸的流入。MCT-1最大速度增加表明rHuEPO可能在骨髓红细胞生成过程中刺激MCT-1的合成。
