The polyphosphoinositide content of the leucocyte, erythrocyte and macrophage

1. The polyphosphoinositide content of macrophages and the cell membranes of leucocytes and erythrocytes was determined by an extension of the ;acid-hydrolysis' procedure of Dawson & Eichberg (1965). The estimation was controlled by adding a little highly radioactive polyphosphoinositide to the tissue extracts before fractionation. Several standard methods for determining polyphosphoinositides gave low recoveries when applied to leucocytes, and it is suggested that these cells contain materials that form complexes with the polyphosphoinositides and interfere with the assay. 2. The method for the preparation of leucocyte cell surface membranes has been modified.