12-LIPOXYGENASE PRODUCT AS AN INHIBITOR OF THE ACTION OF CHEMOATTRACTANT PEPTIDE FMET-LEU-PHE IN RAT NEUTROPHILS

1. 12-Hydroxyeicosatetraenoic acid (12-HETE) has been evaluated for it s capacities to modulate neutrophil migration and cytosolic Ca2+([Ca2]i) using compounds prepared by chemical synthesis and tissue extract from dog gingiva. 2. 12-HETE inhibited N-formyl-Met-Leu-Phe (fMLP)-sti mulated neutrophil migration in a concentration-dependent fashion. 3. The tissue extract from dog gingiva mimicked the actions of 12-HETE. 4 . Although 12-HETE failed to increase [Ca2+]i, preincubation of neutro phils with 12-HETE led to a suppression of [Ca2+]i when the cells were subsequently stimulated by fMLP. 5. Again tissue extract from dog gin giva mimicked the action of 12-HETE on [Ca2+]i. 6. These results sugge st the possible correlation of the inhibitory activities of 12-HETE on the regulation of neutrophil migration and Ca2+ mobilization, and thi s may be important for the role of 12-HETE in pathogenesis in periodon tal tissues.