INHIBITORY EFFECTS OF PROTEIN-KINASE-C IN HIBITOR AND CALMODULIN ANTAGONIST ON TUMOR-NECROSIS-FACTOR PRODUCTION BY MOUSE MACROPHAGES

Mouse peritoneal macrophages were primed with calcium ionophore calcim ycin 1 mumol.L-1 for 8 h and then elicited by lipopolysaccharides (LPS , 10 ng.ml-1) for 6 h to induce tumor necrosis factor (TNF), measured by cristal violet staining assay using murine fibroblast L929 cells. P rotein kinase C (PKC) inhibitor, 1-(5-isoquinolinesulphonyl)-2-methylp iperazine (H-7) and calmodulin (CaM) antagonist, N-(6-aminohexyl)-5-ch loro-1-naphthalenesulfonamide (W-7) were studied on LPS-induced TNF pr oduction by macrophages. Addition of H-7 (0.31-50 mug.ml-1) and W-7 (1 0-4000 ng.ml-1) simultaneously wit LPS to the culture medium suppresse d LPS-induced TNF production in a concentration-dependent manner. When macrophages were pretreated with W-7 (10 ng.ml-1), LPS-induced TNF pr oduction was completely inhibited at 8 h. These results suggest that T NF production by macrophages may be dependent on the PKC and CaM.