Connett R J, Gayeski T E, Honig C R
Am J Physiol. 1985 Jun;248(6 Pt 2):H922-9. doi: 10.1152/ajpheart.1985.248.6.H922.
Rate of O2 consumption (VO2), intracellular PO2, lactate extraction, and tissue contents of phosphocreatine, creatine, ATP, lactate, and pyruvate were measured during rest-work transitions in dog gracilis muscles. Samples were taken at rest and after 5, 10, 15, 30, 60, and 180 s of twitch contraction at 4/s. There was no anoxia at any time or location [companion paper, Am. J. Physiol. 248 (Heart Circ. Physiol. 17): H914-H921, 1985]. Energy was supplied by a continuous utilization of phosphocreatine stores, a slow rise in VO2, and two distinct bursts of glycolysis. Glycolytic rate was independent of tissue PO2 and VO2 and was poorly correlated with phosphocreatine under the aerobic conditions of our experiments. The glycolytic bursts served as a source of ATP, and the bulk of the lactate formed remained in the tissue. Lactate efflux was a small fraction of tissue lactate; it depended on blood flow but not on tissue lactate content. At steady state a small glycolytic flux maintained the high tissue lactate mainly by matching rates of pyruvate production and oxidation. We propose that this flux and the high tissue lactate concentration buffer cytosolic redox and/or substrate supply in support of the aerobic functions of mitochondria during exercise.
在犬股薄肌从静息到工作状态的转变过程中，测量了氧气消耗率（VO2）、细胞内PO2、乳酸摄取以及磷酸肌酸、肌酸、ATP、乳酸和丙酮酸的组织含量。在静息状态以及以4次/秒的频率进行抽搐收缩5、10、15、30、60和180秒后采集样本。在任何时间或位置均未出现缺氧情况[配套论文，《美国生理学杂志》248卷（心脏循环生理学17）：H914 - H921，1985年]。能量通过磷酸肌酸储备的持续利用、VO2的缓慢上升以及两个不同的糖酵解爆发阶段来供应。在我们实验的有氧条件下，糖酵解速率与组织PO2和VO2无关，且与磷酸肌酸的相关性较差。糖酵解爆发阶段作为ATP的一个来源，所形成的大部分乳酸仍留在组织中。乳酸流出量仅占组织乳酸的一小部分；它取决于血流量，但不取决于组织乳酸含量。在稳态时，一个小的糖酵解通量主要通过使丙酮酸生成和氧化速率相匹配来维持组织中高浓度的乳酸。我们提出，这种通量和高组织乳酸浓度缓冲了胞质氧化还原状态和/或底物供应，以支持运动期间线粒体的有氧功能。
