Fernandez-Checa J C, Ren C, Aw T Y, Ookhtens M, Kaplowitz N
Liver Research Laboratory, Wadsworth Veterans Administration Hospital Center, Los Angeles, California.
Am J Physiol. 1988 Oct;255(4 Pt 1):G403-8. doi: 10.1152/ajpgi.1988.255.4.G403.
total glutathione (GSH) efflux was studied in isolated rat hepatocyte suspensions at repleted GSH content (45-55 nmol/10(6) cells). The increase in concentrations of medium K+ in place of Na+ caused a parallel fall in membrane potential and total GSH efflux. Ouabain (1 mM) and replacement of Na+ with choline caused a gradual fall in membrane potential and GSH efflux. Hyperpolarization of hepatocytes with lipophilic anions, thiocyanate, and nitrate was associated with significantly increased efflux. Total GSH efflux was inhibited by increasing concentrations of fructose, antimycin A, and carbonyl cyanide p-trifluoromethoxyphenylhydrazone, and there was a direct relationship between the rate of efflux and cellular ATP. Changes in total GSH efflux were paralleled by changes in GSH determined by high-performance liquid chromatography. Vanadate markedly inhibited efflux but caused only a modest decrease in cellular ATP. Fructose, antimycin A, and vanadate did not affect membrane potential or cell volume under the conditions at which efflux was inhibited. These results suggest independent requirements for both membrane potential and ATP in the transport of GSH.
在谷胱甘肽（GSH）含量充足（45 - 55 nmol/10⁶个细胞）的分离大鼠肝细胞悬液中研究了总谷胱甘肽（GSH）的外排情况。用钾离子替代钠离子使培养基中钾离子浓度升高，导致膜电位和总GSH外排平行下降。哇巴因（1 mM）以及用胆碱替代钠离子会使膜电位和GSH外排逐渐下降。用亲脂性阴离子硫氰酸盐和硝酸盐使肝细胞超极化与外排显著增加相关。总GSH外排受到果糖、抗霉素A和羰基氰对三氟甲氧基苯腙浓度增加的抑制，并且外排速率与细胞ATP之间存在直接关系。通过高效液相色谱法测定的GSH变化与总GSH外排变化平行。钒酸盐显著抑制外排，但仅使细胞ATP适度降低。在抑制外排的条件下，果糖、抗霉素A和钒酸盐不影响膜电位或细胞体积。这些结果表明GSH转运对膜电位和ATP有独立需求。
