Effects of vanadate on intracellular Ca2+ redistribution and hexose transport across plasma membrane in cultured mouse fibroblasts.

The effects of vanadate on intracellular Ca2+ sequestration and hexose transport were studied in Swiss 3T3 cells. Vanadate inhibited ATP-dependent Ca2+ uptake by saponin-permeabilized Swiss 3T3 cells at 10(-5) and 10(-7) M Ca2+ at which the Ca2+ uptake was sensitive and insensitive to oligomycin plus antimycin A, respectively. On the other hand, vanadate stimulated 2-deoxy-D-glucose (2DG) uptake in a dose- and time-dependent way. The stimulation of 2DG uptake by vanadate was inhibited by EGTA plus A23187 and the inhibition was reversed by Ca2+ restoration. These results suggest that an increase in cytosolic Ca2+ by inhibition of intracellular ATP-dependent Ca2+ sequestration by vanadate results in the stimulation of hexose transport in Swiss 3T3 cells.