Effects of lanthanide ions on hydrolysis of phosphatidylinositol in human erythrocyte membranes

The effects of lanthanides on the hydrolysis of phosphatidylinositol in human erythrocyte membranes were studied. ³H-inositol labeling chromatography and HPLC were used to determine inositol 1, 4, 5-triphosphate and diacylglycerol separately, the hydrolytic products of phosphatidylinositol due to the reaction of lanthanide ions with human erythrocyte membranes. The unhydrolyzed phosphatidylinositol in membranes was also determined. The results indicate that the hydrolysis of phosphatidylinositol can be promoted by lanthanides (La³⁺, Ce³⁺, Y³⁺, Tb³⁺) and the effects of La³⁺ and Ce³⁺ are stronger than those of Y³⁺ and Tb³⁺.