Ethanol inhibits zymosan-stimulated and enhances nonstimulated platelet-activating factor production in a clonal macrophage cell line.

Ethanol was examined for its effects on zymosan phagocytosis and synthesis of platelet-activating factor (PAF) using a clonal macrophage cell line. PAF, identified as 1-O-alkyl-2-acetyl-sn-glycerol-3-phosphocholine, is a biologically active ether phospholipid produced by various cells types. PAF also activates a variety of inflammatory cells including the cells which produce PAF. Ethanol at 20 to 100 mM inhibited phagocytosis of unopsonized zymosan and concomitantly decreased PAF concentration in the stimulated macrophages. In contrast, in cells not stimulated with zymosan, ethanol increased the recoverable PAF. Ethanol, at 100 mM, inhibited the uptake of exogenous PAF but did not alter the distribution of PAF metabolites in the clonal macrophage cell line. The effect ethanol has on PAF synthesis appears dependent on the activation state of the cell. Two situations were identified in this study: 1) one linked to phagocytosis or cell stimulation which is inhibited by ethanol, and 2) PAF synthesis which is not dependent on overt cell activation that is enhanced by ethanol.