Membrane potentials, electrolyte contents, cell pH, and some enzyme activities of fibroblasts
Membrane potentials, electrolyte contents, cell pH, and some enzyme activities of fibroblasts
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DOI：
10.1007/bf02618872
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发表时间：
1984-09
期刊：
影响因子：
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通讯作者：
Y. Yen-Chow;S. Chow;W. Jee;D. M. Woodbury
中科院分区：
文献类型：
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作者：
Y. Yen-Chow;S. Chow;W. Jee;D. M. Woodbury
培养的兔皮下成纤维细胞静息膜电位为−10.2±0.2 mV(n=390)。此电位受培养液中钾离子浓度的影响，但不受其他化学或激素制剂的影响，如二丁基腺苷3‘，5’-环一磷酸(0.5~5.0−/L)、氟化钠(10−5~10−4M)、氢化可的松(10−7~10 MU 6M)、甲状旁腺提取物(0.5~1.0U/ml)或促甲状腺激素(5~10mU/ml)。培养的成纤维细胞的Na+、K+和Cl-−浓度分别为35.4、85.7和2 2.6 mmoL/L细胞水。这些细胞的水分和蛋白质含量分别为82.1g/100g细胞和9.18g/100g细胞。用[14C]-二甲基恶唑烷-2，4-二酮和3H2O测定成纤维细胞的细胞内pH，当培养液的pH值保持在7.4时，细胞内的pH在6.9到7.1之间。细胞内Na+、K+-、HCO3−-和Ca++、Mg++-ATPase活性分别为19.0±2.1、13.6±2.1和6.6±1.2nmolpi/mg蛋白/分钟，碳酸氢酶活性为0.054 U/mg蛋白。根据本研究中观察到的膜电位值和电解质浓度的计算表明，Na+、K+、Cl−和H+不是按照它们在细胞膜上的电化学梯度分布的。Na+、Cl-−和H+被主动地转运出细胞，K+被转运到细胞内。
The resting membrane potential of the cultured fibroblasts derived from rabbit subcutaneous tissues was −10.2±0.20 mV (n=390). This potential was affected by the potassium concentration in the culture medium, but not by other chemical or hormonal preparations, such as dibutyryladenosine 3′,5′-cyclic monophosphate (0.5 to 5.0 mmol/l), sodium fluoride (10−5to 10−4M), hydrocortisone (10−7to 10−6M), parathyroid extract (0.5 to 1.0 U/ml), or thyrotrophin (5 to 10 mU/ml). The Na+, K+, and Cl−concentrations of the cultured fibroblasts were 35.4, 85.7, and 22.6 mmol/l cell water, respectively. The water and protein contents of these cells were 82.1 and 9.18 g/100-g cells, respectively. The intracellular pH of fibroblasts as determined by [14C] dimethyloxazolidine-2, 4-dione, and3H2O ranged between 6.9 and 7.1 when the pH of the culture medium was maintained at 7.4. The activiities of Na+, K+-, HCO3−-, and Ca++, Mg++-ATPases in these cultured cells were 19.0±2.1, 13.6±2.1, and 6.6±1.2 nmol pi/mg protein per minute, respectively, and the carbonic anhydrase activity was 0.054 U/mg protein. Calculations based on the values for the membrane potential and the electrolyte concentrations observed in this study indicate that Na+, K+, Cl−, and H+are not distributed according to their electrochemical gradients across the cell membrane. Na+, Cl−, and H+are actively transported out of the cells and K+into the cells.