Nitric oxide modulates prostacyclin biosynthesis in the lung of endotoxin-treated rats.

In this study we have investigated the correlation between prostaglandin generation and the L-arginine:nitric oxide (NO) pathway in the lung of rats challenged with lipopolysaccharide. We found that in rats treated with L-arginine, the amount of prostacyclin, measured as 6-keto-PGF1 alpha, was significantly increased. Conversely in rats treated with NG-nitro-L-arginine methyl ester the production of 6-keto-PGF1 alpha by lung was significantly decreased. Chopped lungs that had been removed from rats challenged with lipopolysaccharide and were incubated overnight with L-arginine or nitric oxide inhibitors, NG-nitro-L-arginine methyl ester or NG-monomethyl-L-arginine, released respectively increased or decreased amount of 6-keto-PGF1 alpha. These results suggest that, in the rat, lung endogenous nitric oxide may modulate prostanoid production.