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

The effects of lanthanides on the hydrolysis of phosphatidylinositol in hum an erythrocyte membranes were studied. H-3-inositol labeling chromatography and HPLC were used to determine inositol 1, 4, 5-triphosphate and diacylgl ycerol separately, the hydrolytic products of phosphatidylinositol due to t he reaction of lanthanide ions with human erythrocyte membranes. The unhydr olyzed phosphatidylinositol in membranes was also determined. The results i ndicate that the hydrolysis of phosphatidylinositol can be promoted by lant hanides (La3+, Ce3+, Y3+, Tb3+) and the effects of La3+ and Ce3+ are strong er than those of Y3+ and Tb3+.