Role of kinases and G-proteins on arachidonate release induced by zymosan in mouse peritoneal macrophages.

The present study investigated the role of kinases and G-proteins in arachidonic acid (AA) mobilization by resident mouse peritoneal macrophages in response to phagocytosis of opsonized zymosan. Stimulation of resident murine peritoneal macrophages with opsonized zymosan caused an increase in [3H] arachidonic acid release. This increase was dose-dependent and was not accompanied by de novo synthesis of proteins. Neither staurosporine, a protein kinase C inhibitor, nor genistein, a tyrosine kinase inhibitor, had any effect on [3H] AA mobilization, although trifluoperazine significantly inhibited AA release. The involvement of G proteins and phospholipase C (PLC) in the regulation of arachidonic acid release induced by opsonized zymosan was also examined in mouse peritoneal macrophages. Prior treatment of cells with pertussis toxin induced a partial decrease in AA mobilization. However, neomycin or aspirin, at doses that inhibit inositol phosphate formation (PLC activity), did not [3H] AA mobilization by PLA2. We proposed that the AA release by peritoneal macrophages in response to opsonized zymosan phagocytosis could be due to the participation of enzymes other than PLC and PKC, or proteins other than G proteins.