CORRELATION BETWEEN NITRIC-OXIDE SYNTHASE ACTIVITY AND REDUCED GLUTATHIONE LEVEL IN HUMAN AND MURINE ENDOTHELIAL-CELLS

The synthesis of nitric oxide (NO), detected as citrulline production, in human (HUVEC) and murine (tEnd.1) endothelial cells correlated wit h intracellular GSH. tEnd.1, which exhibited an intracellular GSH leve l 2.5-fold higher than HUVEC, showed a citrulline production (basally and after ionomycin stimulation) 5-8 times higher than human cells. Io nomycin-elicited citrulline synthesis in tEnd.1 cells increased 2.4-fo ld after loading with GSH, and decreased dose-dependently after GSH de pletion. Cell loading with N-(2-mercaptopropionyl)-glycine neither sig nificantly increased citrulline production nor relieved the effect of GSH depletion.