[Sugar transport regulation in vitro by new calcium ionophores]

The influence of calcium ionophores--tenoyltrifluoroacetate (TTFA) and divaleryldibenzo-18-crown-6(divaleryl) on the glucose consumption, D-xylose transport and glycogen content in rat diaphragm was studied. TTFA caused a clear dose-dependent inhibition of carbohydrate transport and glycogenolysis stimulation. Divaleryl, on the other hand, raised glucose consumption, D-xylose transport without influencing glycogen content. Exclusion of Ca++ from incubation medium increased the TTFA inhibiting effect on glucose consumption, decreased its glycogenolytic effect and removed divaleryl induced stimulation of glucose transport. Mechanisms of calcium ionophore action and a possible role of intracellular Ca2+ in carbohydrate transport are discussed.