Effect of prostaglandin- and nitric oxide-synthase inhibitors on the lipopolysaccharide-induced adrenomedullin productions in cultured murine macrophage cells / 대한산부인과학회지

ABSTRACT

OBJECTIVE: Adrenomedullin (AM), a potent vasorelaxing agent associated with the maintenance of pregnancy, is synthesized in response to inflammation, which is also associated with the biosynthesis of prostaglandin (PG) and nitric oxide (NO). To clarify the interrelationships of PG, NO and AM in the inflammatory process, we tested the effects of the PG synthase inhibitor indomethacin and the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) on AM production in lipopolysaccharide (LPS)-stimulated cultured rat macrophages. METHODS: RAW 257.8, rat macrophages were incubated with LPS, and AM production was measured by ELISA. Cells were pretreated with indomethacin, L-NAME, or both, and the effect on LPS-induced AM production was assayed. To exclude the effect of cell death, a cell viability test on these cultures was performed. RESULTS: The largest increase of AM was seen between 1 microgram (36.33+/-2.05 pg/ml) and 10 microgram (89.33+/-6.02 pg/ml) of LPS concentration (p<0.01), making the latter the optimal LPS dose to stimulate AM production. AM secretion was proportional to time in culture (p<0.006). Addition of indomethacin, L-NAME, or both 1 hr before LPS stimulation decreased AM production 2 hr later, with the AM decrement greatest in cells pretreated with both indomethacin and L-NAME, followed by L-NAME alone and then indomethacin. CONCLUSION: These findings indicate that PG and NO increase AM synthesis in rat macrophages with the presence of LPS. These results suggest that the biosynthetic pathways of PG, NO, and AM may be linked.