Effect of neomycin and ionophore A23187 on ATP levels and turnover of polyphosphoinositides in human erythrocytes

Abstract

The relationship of polyphosphoinositide metabolism to erythrocyte ATP levels was examined. Turnover of polyphosphoinositides was not as closely dependent on ATP as it is reported to be in yeast. Neomycin increased 32P incorporation into diphosphoinositide and to a lesser extent into triphosphoinositide without affecting intracellular ATP. Treatment of intact cells with ionophore A23187 resulted in a decrease of at least 80% in polyphosphoinositide levels which followed a decrease in cellular ATP and an increase in phosphatidate. The results indicate that polyphosphoinositide turnover does not regulate energy charge in the erythrocyte. However some of the events which follow treatment of erythrocytes with metabolic inhibitors or calcium and ionophore may be related to the accompanying decrease in polyphosphoinositide levels.