Enhancement of human neutrophil responses to platelet activating factor by 5(S)-hydroxy-eicosatetraenoate

5(S)-hydroxy-eicosatetraenoate (5(S)-HETE) enhanced the ability of platelet-activating factor (PAF) to stimulate neutrophil inositol phospholipid turnover, Ca2+ transients, superoxide anion generation, and degranulation. It did not alter responses to leukotriene B4, N-formyl-methionylleucylphenylalanine, or ionomycin. Moreover, 5(R)- and 15(S)-HETE had little effect on PAF. 5(S)-HETE thus acted stereospecifically and stimulus-selectively to potentiate early occurring transductional events as well as later occurring functional responses to PAF. The HETE may influence the actions of PAF by up-regulating PAF receptors and/or these receptors' linkages with the G-protein/phospholipase C axis.