Ethanol effects on active Na+ and K+ transport in cultured fetal rat hepatocytes.
Ethanol effects on active Na+ and K+ transport in cultured fetal rat hepatocytes.
复制标题
乙醇对培养的胎鼠肝细胞中活性钠和钾转运的影响。
DOI：
10.1016/0006-2952(89)90543-1
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发表时间：
1989
影响因子：
5.8
通讯作者：
Schenker,S
中科院分区：
文献类型：
--
作者：
McCall,D;Henderson,GI;Gray,P;Schenker,S
为了进一步确定乙醇对膜的影响，在胎鼠肝细胞单层培养中研究了其对Na+泵功能的影响。在细胞暴露于乙醇1 - 24小时后，测定乙醇（2和4mg/ml）对总K+内流、哇巴因敏感性K+内流、Na+泵密度（来自[~3H]哇巴因结合）、泵转换率和细胞内Na+的影响，同时测定乙醇（2mg/ml）对细胞含水量和膜流动性的影响。乙醇对K+内流没有立即的影响，但在1小时后，浓度为2和4 mg/ml的乙醇使总K+内流（μ mol/10~（11）cells/sec）分别从对照组的8.5 ± 0.64降至4.46 ± 0.50和4.09 ± 0.26（每个实验N = 6; P <0.001）。这代表了乙醇的最大作用，因为在乙醇处理6和24小时后，K+内流增加到对照水平，但仍显著增加。（2 mg/ml组P <0.01，4 mg/ml组P <0.001）低于对照组。在用2和4 mg乙醇/ml培养基处理1小时后，内流从对照组的5.87分别增加到3.24和2.70（μ mol/1011细胞/秒）。乙醇（2mg/ml）处理1h使Na+泵密度（× 105分子哇巴因/细胞）由对照组的2.80 ± 0.30降至1.70 ± 0.11（P <0.001）。在6和24小时[3H]哇巴因结合表现出类似的模式，所看到的K+流入，倾向于返回到预处理水平。在乙醇存在下，单个泵的周转率没有变化。暴露于乙醇后，细胞Na+含量在前6小时内稳步增加，然后恢复到对照水平。然而，当校正细胞体积的平行变化时，细胞内Na+浓度在1小时后增加了17%（P <0.01），此后在整个24小时期间保持在该较高水平。膜流动性的测定结果表明，乙醇浓度为2mg/ml时，膜流动性明显增加，其作用与K~+内流和Na~+泵密度的变化有密切的时间关系。我们得出结论，乙醇对肝Na+泵功能有抑制作用，导致细胞内Na+增加，最终增加细胞水。结果表明，这是由于功能Na+泵的数量减少，可能是由于乙醇对质膜的增溶作用。
To define further the influence of ethanol on membranes, its effects on Na+pump function were studied in monolayer cultures of fetal rat hepatocytes. The effects of ethanol (2 and 4 mg/ml) on total K+influx, ouabain-sensitive K+influx, Na+pump density (from specific [3H]ouabain binding), pump turnover rates and intracellular Na+were measured following exposure of the cells to ethanol for 1–24 hr. In parallel studies, the effects of ethanol (2 mg/ml) on cell water content and membrane fluidity were measured. Ethanol had no immediate effect on K+influx, but after 1 hr ethanol in concentrations of 2 and 4 mg/ml decreased the total K+influx (μmol/1011cells/sec) from a control of 8.5 ± 0.64 to 4.46 ± 0.50 and 4.09 ± 0.26 respectively (N = 6 for each experiment; P < 0.001). This represented the maximum effect of ethanol since after 6 and 24 hr of ethanol treatment the K+influx had increased towards control levels but remained significantly (P < 0.01 for 2 mg/ml and P < 0.001 for 4 mg/ml) below that in control cells even at 24 hr. The decrease in K+influx reflected a decrease in mean ouabain sensitive K+influx from a control of 5.87 to 3.24 and 2.70 (μmol/1011cells/sec) after a 1-hr treatment with 2 and 4 mg ethanol/ml medium respectively. Ethanol (2 mg/ml) treatment for 1 hr decreased Na+pump density (× 105molecules ouabain per cell) from a control of 2.80 ± 0.30 to 1.70 ± 0.11 (P < 0.001). At 6 and 24 hr [3H]ouabain binding showed a pattern similar to that seen with the K+influx, tending to return to pretreatment levels. There was no change in individual pump turnover rates in the presence of ethanol. Following exposure to ethanol, cellular Na+content steadily increased over the first 6 hr and then returned to control levels. When corrected for parallel changes in cell volume, however, intracellular Na+concentration increased by 17% (P < 0.01) after 1 hr and thereafter remained at this higher level throughout the 24-hr period. Measurements of membrane fluidity showed that it was increased markedly by ethanol at a concentration of 2 mg/ml and that the effect bore a close temporal relationship to the changes in active K+influx and Na+pump density. We conclude that ethanol has a depressant effect on hepatic Na+pump function, resulting in an increase in intracellular Na+and an eventual gain in cell water. The results suggest that this is due to a decrease in the number of functional Na+pumps, possibly resulting from the solubilizing effect of ethanol on the plasma membrane.