IMPLICATION OF PARATHYROID-HORMONE FOR THE DEVELOPMENT OF HYPERTENSION IN YOUNG SPONTANEOUSLY HYPERTENSIVE RATS

The purpose of this study is to elucidate the role of parathyroid horm one (PTH) in the development of hypertension in young spontaneously hy pertensive rats (SHR), Parathyroidectomy (PTX) or sham surgery was per formed on 6-week-old male SHR, and 3 weeks later human PTH (hPTH) or s aline was infused subcutaneously over 2 weeks using a minipump. PTX si gnificantly attenuated the development of hypertension and reduced ser um vitamin-D concentrations. PTX also augmented the depressor response to acetylcholine before N-nitro-L-arginine (L-NNA), although it remai ned unchanged after L-NNA. The cardiovascular reactivity to exogenous noradrenaline and angiotensin II was not affected by PTX. The chronic administration of hPTH reversed these effects, We conclude that PTH pl ays an important role in the development of hypertension, through modu lating the release of endothelium-derived relaxing factor, in young SH R.