Effect of Escherichia coli heat-stable enterotoxin (ST) on calcium uptake by rat intestinal Brush-Border Membrane Vesicles (BBMV)

Abstract A partially purified Escherichia coli heat-stable (ST) enterotoxin had been shown to increase the ⁴⁵Ca²⁺ uptake by rat intestinal brush-border membrane vesicles (BBMV). The effect of ST enterotoxin on calcium uptake by BBMV was significant compared with the control and was also dose-dependent. The stimulation of calcium uptake by ST enterotoxin was inhibited by chemical agents which block the calcium entry into the cell. These data indicate that the ST acts as calcium ionophore in this particular system.