采用递增负荷跑台运动探讨丙酮酸透膜与乳酸穿梭关系的研究

目的:探讨丙酮酸透膜与乳酸穿梭的关系。方法:不同运动能力的20名男性大学生分为运动组和对照组,每组10人,连续进行不同最大摄氧量百分比递增强度跑台运动,每级负荷运动3分钟,3分钟末取血,测试受试者血乳酸和丙酮酸浓度。结果:(1)运动组乳酸阈平均值出现在75%最大摄氧量强度,对照组出现在65%最大摄氧量强度,两组各级负荷血乳酸值与上一级负荷比较均有显著或非常显著性差异(P<0.05,P<0.01,P<0.001)。(2)对照组各级负荷下血丙酮酸浓度与上一级负荷比较均无显著性差异(P>0.05),运动组在75%、95%最大摄氧量强度下的血丙酮酸浓度与上一级负荷比较有显著性差异(P<0.05,P<0.01)。结果表明:(1)丙酮酸在乳酸阈之前不能或不易透过肌细胞膜。(2)提示丙酮酸透膜与运动强度、时相有关,其机制可能与乳酸穿梭到一定程度有关。

The Relationship between Pyruvate Membrane Permeability and Lactate Shuttle during Incremental Treadmill Exercise

Purpose To study the relationship between pyruvate membrane permeability and lactate shuttle through observing the dynamic changes in the levels of venous blood pyruvate and lactate at different phases of incremental exercise.Methods Twenty male undergraduates were divided into two groups: exercise group and control group,each group contained 10 students.Subjects in exercise group were from PE major and subjects in control group were from non-PE major.They performed treadmill exercise with incremental intensity(3mins/each step).Blood was drawn at the end of each step.Results (1) The lactate thresholds in exercise group and control group were 75%VO2max and 65%VO2max,respectively.(2)In the control group,the level of pyruvate at each intensity was not significantly different from that at preceding intensity(P>0.05).In exercise group,the level of pyruvate at 75% of VO2max and 95% of VO2max were significantly different from that at preceding intensity(P<0.05 and P<0.01,respectively) Conclusion (1) Pyruvate is unable or difficult to pass through the membrane of myocyte.(2) Pyruvate membrane permeability is related to the exercise intensity and the phase of exercise,and its mechanism is different from that of lactate shuttle.