Reyes J G, Velarde M V, Ugarte R, Benos D J
Instituto de Quimica, Universidad Catolica de Valparaiso, Chile.
Am J Physiol. 1990 Oct;259(4 Pt 1):C660-7. doi: 10.1152/ajpcell.1990.259.4.C660.
The impact of glycolysis on rat spermatid energy metabolism is made apparent by the simultaneous occurrence of the following three events upon glucose addition to the extracellular medium of a rat spermatid cell suspension: decrease in ATP content, exit of acid equivalents, and increased lactate production and efflux. In this work, we have studied the interrelations between these three phenomena. By measuring ATP content, net acid transport, lactate exit, oxygen consumption, intracellular pH, CO2 production, and glycolytic intermediates in the presence of glucose and glucose analogues, we conclude that 1) lactate production, decrease in ATP content, and acid equivalent exit are dependent on the metabolism of glucose up to different stages in glycolysis. 2) The decrease in ATP content is not directly related to the exit of acid equivalents from rat spermatids. 3) Glucose metabolism is a net ATP-consuming process at high intracellular ATP content but is a net ATP-producing process at low intracellular ATP concentration in rat spermatids. 4) Acid equivalent production arises from the metabolism of glucose beyond glyceraldehyde 3-phosphate dehydrogenase. 5) Lactic acid diffusion and/or lactate transport and CO2 production and exit could account for the glucose-dependent acid equivalent efflux in rat spermatids.
当向大鼠精子细胞悬液的细胞外培养基中添加葡萄糖时，同时发生以下三个事件，这表明糖酵解对大鼠精子能量代谢的影响：ATP含量降低、酸当量流出以及乳酸生成和流出增加。在这项研究中，我们研究了这三种现象之间的相互关系。通过在葡萄糖和葡萄糖类似物存在的情况下测量ATP含量、净酸转运、乳酸流出、耗氧量、细胞内pH值、二氧化碳生成和糖酵解中间产物，我们得出以下结论：1）乳酸生成、ATP含量降低和酸当量流出取决于糖酵解不同阶段的葡萄糖代谢。2）ATP含量的降低与大鼠精子中酸当量的流出没有直接关系。3）在大鼠精子中，当细胞内ATP含量高时，葡萄糖代谢是一个净消耗ATP的过程，但当细胞内ATP浓度低时，它是一个净产生ATP的过程。4）酸当量的产生源于葡萄糖在甘油醛-3-磷酸脱氢酶之后的代谢。5）乳酸扩散和/或乳酸转运以及二氧化碳生成和流出可以解释大鼠精子中葡萄糖依赖性酸当量的流出。
