Further studies on murine macrophage synthesis of nitrite and nitrate

Further studies on macrophage synthesis of nitrite and nitrate showed lipopolysaccharide (LPS) and interferon (IFN) to be potent stimuli. Kinetic experiments showed a time lag of 6 h for LPS and 10-12 h for IFN. The protein synthesis inhibitor cycloheximide completely inhibited nitrite and nitrate synthesis when present in the media at time 0 but had no effect if added at times after the lag period. A number of experiments were carried out to test the involvement of reactive oxygen species (the 'oxygen burst') in stimulated macrophage synthesis. All results were consistent with a lack of involvement of the oxygen burst in this process.