[Effects of L-arginine on acute hypoxic pulmonary hypertension and production of endothelin-1 in vivo and in cultured endothelial cells].

This study is aimed to investigate the effects of L-arginine, a precursor of the formation of nitric oxide, on acute hypoxic pulmonary hypertension in vivo and on production of endothelin-1 both in vivo and in cultured endothelial cells. In mechanically ventilated anesthetized dogs (n = 7), L-arginine (0.5 g/kg) reduced the mean pulmonary arterial pressure and femoral arterial pressure during hypoxic ventilation and its action lasted for about 30 minutes. Meanwhile, plasma endothelin-1 in the pulmonary and femoral artery had no remarkable change. In cultured endothelial cells from umbilical veins, different concentrations of L-arginine had no influence on endothelin-1 level of culture medium in 4 or 24 hours after the addition of L-arginine. These results indicate that L arginine can decrease the pulmonary arterial pressure during acute hypoxia, which may be associated with the increase of nitric oxide production.