Clegg J S
University of California, Bodega Marine Laboratory, CA 94923.
Cell Biophys. 1988 Oct;13(2):119-32. doi: 10.1007/BF02796975.
Changes in cell water content resulting from sorbitol addition to the environment of L-929 cells were evaluated gravimetrically using 14C-labeled polyethylene glycol as a probe of extracellular space. Reductions in cell water were proportional to sorbitol supplements up to 0.6 molal, above which no further measurable decrease occurred. No volume regulation occurred for at least 1 h but the percentage of cell water lost was quickly regained when physiological conditions were restored. The amount of cell water lost because of a given hyperosmotic exposure was found to exceed the loss of cell volume. That discrepancy could be the result of an overestimation of extracellular space and/or an underestimation of cell volume reduction as a result of in-folding of the cell surface. Na+ and K+ were also measured in cells of variable water content and volume: no significant change occurred in the amounts of these ions per cell, but large increases in total cell concentration resulted from hyperosmotic exposure. The sum of Na+ and K+ concentrations exceeds the total osmotic pressure of the medium indicating that an appreciable fraction of Na+ and K+ must be bound to fixed charges within the cells. The results are evaluated in the context of intracellular organization.
通过使用14C标记的聚乙二醇作为细胞外空间的探针，采用重量法评估了向L-929细胞环境中添加山梨醇后细胞含水量的变化。细胞内水分的减少与高达0.6摩尔浓度的山梨醇添加量成正比，超过该浓度后，未观察到进一步的可测量减少。至少1小时内未发生体积调节，但当恢复生理条件时，细胞丢失的水分百分比迅速恢复。发现由于给定的高渗暴露而导致的细胞水分丢失量超过了细胞体积的减少量。这种差异可能是由于细胞外空间的高估和/或由于细胞表面内折导致的细胞体积减少的低估。还测量了含水量和体积可变的细胞中的Na+和K+：每个细胞中这些离子的量没有显著变化，但高渗暴露导致细胞总浓度大幅增加。Na+和K+浓度的总和超过了培养基的总渗透压，这表明相当一部分Na+和K+必须与细胞内的固定电荷结合。在细胞内组织的背景下对结果进行了评估。
