Bogner P, Berke T, Kellermayer M
Department of Clinical Chemistry, University Medical School, Pécs, Hungary.
Physiol Chem Phys Med NMR. 1992;24(4):281-8.
Most, if not all, cells maintain an unequal distribution of Na+ and K+ against their environment. These two monovalent ions are in constant exchange between the cell and the extracellular space since both ions have proved to be permeable through the cell membrane. The distribution of Na+ and K+ in intact and "sucrose-permeabilized" rat lymphocytes were studied ("sucrose-permeabilization" means homogenization in isotonic sucrose solution). Both the intact and the permeabilized lymphocytes were incubated in Hanks' solution and then transferred into K+, Na(+)-free isotonic sucrose solution. Alternatively, the cells were incubated only in the sucrose solution or in Hanks' solution. The Na+ and K+ content of the cells were determined at the conclusion of each period of incubation in the same or different medium. We found that K+ did not equilibrate under any conditions in intact lymphocytes but Na+ responded to changes of the incubation media. In the permeabilized cells Na+ freely equilibrated with the extracellular medium while K+ did not, although its concentration decreased compared to that of intact cells.
大多数（即便不是全部）细胞相对于其周围环境维持着Na⁺和K⁺的不均衡分布。这两种单价离子在细胞与细胞外空间之间持续进行交换，因为这两种离子都已被证明可透过细胞膜。研究了完整的和“蔗糖通透化”的大鼠淋巴细胞中Na⁺和K⁺的分布情况（“蔗糖通透化”是指在等渗蔗糖溶液中进行匀浆）。完整的和通透化的淋巴细胞均先在汉克斯溶液中孵育，然后转移至无K⁺、无Na⁺的等渗蔗糖溶液中。或者，细胞仅在蔗糖溶液或汉克斯溶液中孵育。在相同或不同培养基中每个孵育阶段结束时测定细胞的Na⁺和K⁺含量。我们发现，在完整淋巴细胞中，K⁺在任何条件下都不会达到平衡，但Na⁺会对孵育培养基的变化做出反应。在通透化细胞中，Na⁺可与细胞外培养基自由达到平衡，而K⁺则不能，尽管其浓度与完整细胞相比有所降低。
