ラット腹水肝癌AH66細胞におけるビンブラスチンの膜透過機序の検討

抄録

The influence of Ca²⁺ antagonists and metabolic inhibitors on the membrane transport of vinblastine (VBL) in rat ascites hepatoma AH66 cells was investigated. Such Ca²⁺ antagonists as ruthenium red (RR) and lanthanum chloride (La) decreased the uptake of VBL but did not influence the intracellular retention of VBL. In contrast, verapamil markedly increased the uptake and decreased the efflux of VBL. Since AH66 cells are not excitable cells, it was considered that verapamil which is a Ca²⁺ channel antagonist showed a different action from other Ca²⁺ antagonists. Iodoacetic acid increased the uptake of VBL and suppressed the extrusion of VBL but dinitrophenol and ouabain did not influence the intracellular content of VBL in the glucose rich medium. On the other hand, RR and La specifically inhibited the activity of (Ca²⁺-Mg²⁺) ATPase. Ouabain also specifically inhibited the activity of (Na⁺-K⁺) ATPase. Iodoacetic acid suppressed the activities of ATPase except (Na⁺-K⁺) ATPase. Therefore, in the influx of VBL, the presence of Ca²⁺ on the plasma membrane or in the cell seemed to be necessary. Moreover, it was suggested that VBL was not extruded by neither (Na⁺-K⁺) ATPase nor (Ca²⁺-Mg²⁺) ATPase in the plasma membrane and a different active transport system might be concerned with the efflux of VBL.