Direct evidence of nitric oxide production induced by lactoferrin and its enhancement by magnesium ions in cultured endothelial cells.

Bovine lactoferrin (BLF) reportedly lowers blood pressure and induces vasorelaxation, but its effect on nitric oxide (NO) production has not been established. Accordingly, we aimed to determine whether BLF induces NO production in bovine aortic endothelial cells, and the effects of extracellular free magnesium (Mg) ion concentrations on this NO production. BLF induced NO production time-dependently. NO production was markedly inhibited by the NO synthase inhibitor, N-nitro-L-arginine methyl ester, in an effect abolished by L-arginine, but not D-arginine. NO production was suppressed at low concentrations, and enhanced at high concentrations, of Mg ions in culture medium. These results suggest that BLF has an important role in hypotensive effects. Mg ions may affect BLF-induced NO production.