Energy-requiring uptake of protoberberine alkaloids by cultured cells ofThalictrum flavum.
Cultured cells ofThalictrum flavum take up berberine exogenously added to medium against the concentration gradient. This uptake was temperature-dependent and sensitive to plasma membrane-bound ATPase inhibitors such as sodium orthovanadate and diethylstilbestrol, indicating that the process is mediated by an energy-requiring system. The time-course of pH-shift during berberine uptake suggests the participation of a berberine-proton antiport system in the berberine uptake by the cultured cells. In addition, the existence of a specific transport system was suggested by the competitive inhibition of berberine uptake by berberine analogues, coptisine and jatrorrhizine.
Faculty of Pharmaceutical Sciences, Kyoto University, 606, Kyoto, Japan.
H
H
Yamamoto
M
M
Suzuki
T
T
Kitamura
H
H
Fukui
M
M
Tabata