Abstract: ObjectiveTo investigate the mechanism on endothelial dysfunction of spontaneous hypertensive rats (SHR).MethodsThe animals were divided into two groups: SHRs (n=8) and Wistar-Kyoto (WKY) rats (n=7) all aged 17 months. Blood pressure was measured by the tail-cuff method. NO₃^- concentration in serum was assayed by activated cadmium reduction method; endothelin (ET) and cGMP levels were assayed by RIA.ResultsCompared with WKY rats, blood NO_{3^- concentration, ET level and vascular cGMP level of SHRs were all reduced significantly (P<0.01); vascular ET level was only uplifted slightly with no significant difference (P>0.05).ConclusionIt indicates that the vascular endothelial dysfunction in SHR is induced possibly by a diminished synthesis or release of NO, not by changes of ET level.}

Key words: hypertension, endothelin (ET), nitric oxide