Effect of hypoxia on nitric oxide production and its synthase gene expression in rat smooth muscle cells

It has not been clarified yet as to whether hypoxia and inflammation affect NO synthesis. In this study, we investigated the transcription of inducibl e nitric oxide synthase (iNOS) mRNA and the production of nitric oxide (NO) in rat smooth muscle cells (SMCs) cultured under hypoxic conditions in the presence and absence of proinflammatory cytokine interferon-gamma (IFN-gam ma) and lipopolysaccharide (LPS), We found that hypoxia inhibited the produ ction of NO but did not affect the transcription of iNOS mRNA in rat SMCs t reated with IFN-gamma, LPS, or both, These results indicate that O-2 is inv olved in the regulation of NO synthesis in inflammatory tissues. (C) 2000 A cademic Press.