INTERACTIONS OF 1-O-ALKYL-2-METHOXY-SN-GLYCERO-3-PHOSPHOCHOLINE AND PLATELET-ACTIVATING-FACTOR WITH BLOOD AND TUMOR-CELLS

The effects of platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn- glycero-3-phosphocholine) and its methoxy analog(methoxy-PAF; 1-O-alky l-2-methoxy-sn-glycero-3-phosphocholine) on platelet aggregation, neut rophil oxidative metabolism, and proliferation of human erythroleukemi a (K-562) and murine mastocytoma (P-815) cells have been studied. With platelets and neutrophils PAF and methoxy-PAF were nearly equally act ive, while the cytotoxic effect of the analog was much more pronounced than that of the natural compound. Thus, the biological activity of m ethoxy-PAF appears to be based on its structural similarity to PAF. Th e inability of the cells to rapidly metabolize and utilize the analog may also contribute to the observed effects.