Nitric oxide production by murine macrophages is inhibited by prolonged elevation of cyclic AMP

Murine macrophages produce large amounts of nitric oxide (NO) on stimulation by interferon (IFN)-gamma and lipopolysaccharide (LPS) or a high concentration of LPS alone. Agents which increase intracellular cAMP levels inhibit cytokine production by macrophages. The effect of increased intracellular cAMP levels on NO production was investigated, using a murine macrophage cell line, J774. NO production was reduced by prolonged elevation of cAMP, but not by a transient increase.