ABSTRACT
PurposeTo study the changes of serum nitric oxide(NO)and endothelin(ET)levels by L-Arg therapy in acute hypoxic model. MethodsNADPH diaphorase histochemical staining method, Griess biochemical assay and radioimmune assay were applied to investigate the changes of nitric oxide synthase (NOS) ,NO, cGMP and ET in normal, hypoxic and L-Arg treated hypoxic rats. Resultsduring acute hypoxia, while serum ET rose up significantly, both the levels of serum NO and cGMP and the activity of NOS were significantly lower. After the application of L-Arg therapy, the activity of NOS did not change significantly, but the levels of serum NO and cGMP rose up significantly, and the level of serum ET was to the opposite direction. ConclusionsNO and ET may modulate hypoxic pulmonary hypertension, and acute hypoxia can result in acute hypoxic pulmonary hypertension. L-Arg can reverse the acute hypoxic hypertension.