Possible involvement of protein kinase C in interleukin-1 production by mouse peritoneal macrophages.

Both lipopolysaccharide (LPS) and phorbol-12,13-dibutyrate (PDBu), a protein kinase C-activating phorbol ester, induced interleukin-1 (IL-1) production in mouse peritoneal macrophages. Prolonged treatment of the cells with PDBu led to the down-regulation and complete disappearance of protein kinase C. In these cells, PDBu did not increase IL-1 production, but LPS still stimulated IL-1 production although the maximum level was slightly reduced. These results suggest that protein kinase C and another unknown signal pathway are involved in LPS-induced IL-1 production.