Influence of Culture Medium on Production of Nitric Oxide and Expression of Inducible Nitric Oxide Synthase by Activated Macrophages In Vitro

Activated macrophage phenotypes were influenced by the culture medium; a murine macrophage-like cell line, J774.1/JA-4, expresses different activated-macrophage phenotypes induced by lipopolysaccharide (LPS) and/or interferon-γ (IFN-γ) when the cells are incubated in either Ham’s F-12 medium (F-12) or Dulbecco’s modified Eagle medium (DMEM). Among these phenotypes, NO production and iNOS expression are the most remarkably influenced by the medium; the induction of iNOS mRNA and iNOS protein is higher in DMEM than in F-12, but NO production by activated macrophages is less in DMEM than in F-12. These results suggest that the interpretation of the experimental results requires consideration of the possibility that the differences obtained by different laboratories were caused by the culture medium used.