Montrose M H, Condrau M A, Murer H
Physiology Institute, University of Zurich, Switzerland.
J Membr Biol. 1989 Apr;108(1):31-43. doi: 10.1007/BF01870423.
Suspensions of OK cells (a continuous renal epithelial cell line originating from the opossum kidney) were examined by flow cytometry. Three parameters were evaluated simultaneously; cell integrity as assayed by propidium iodide fluorescence, cell size as measured by time-of-flight, and intracellular pH as measured by fluorescence of 2',7'-bis-(2-carboxyethyl)-5,6 carboxyfluorescein (BCECF). The suspension was shown to be composed of both intact singlets and doublets of cells, and no difference was noted in the behavior of these two populations with respect to the resting intracellular pH, or of the response of intracellular BCECF to changes in pH. Evidence suggests that using NH4 prepulses to create an acid load broadens the intracellular pH distribution. The population of OK cells demonstrates a recovery from this acid load which is very homogeneous with respect to its sensitivity to Na+ removal of EIPA (ethylisopropyl-amiloride), suggesting that virtually all cells utilize Na+/H+ exchange for this recovery. The data also suggest heterogeneity in the cellular pH recovery from an acid load with respect to the observed rates of Na+/H+ exchange. Despite this heterogeneity, the Na+/H+ exchanger is observed to focus the resting intracellular pH of the population to approximately pH 7.4-7.5. The response of the population to PTH suggests that the majority of cells respond to the hormone, and that the total Na+/H+ exchange in individual cells is only partially inhibited even in the presence of saturating PTH concentrations.
通过流式细胞术检测了OK细胞（一种源自负鼠肾脏的连续肾上皮细胞系）的悬浮液。同时评估了三个参数：用碘化丙啶荧光检测的细胞完整性、用飞行时间测量的细胞大小以及用2',7'-双（2-羧乙基）-5,6-羧基荧光素（BCECF）荧光测量的细胞内pH值。结果表明，该悬浮液由完整的单细胞和双细胞组成，并且在静息细胞内pH值方面，这两个群体的行为没有差异，细胞内BCECF对pH值变化的反应也没有差异。有证据表明，使用NH4预脉冲产生酸负荷会拓宽细胞内pH值分布。OK细胞群体显示出从这种酸负荷中恢复的情况，就其对EIPA（乙基异丙基氨氯地平）去除Na+的敏感性而言，这种恢复非常均匀，这表明几乎所有细胞都利用Na+/H+交换进行这种恢复。数据还表明，在从酸负荷恢复细胞内pH值方面，就观察到的Na+/H+交换速率而言存在异质性。尽管存在这种异质性，但观察到Na+/H+交换器将群体的静息细胞内pH值集中到大约pH 7.4 - 7.5。该群体对甲状旁腺激素（PTH）的反应表明，大多数细胞对该激素有反应，并且即使在存在饱和PTH浓度的情况下，单个细胞中的总Na+/H+交换也只是部分受到抑制。
