ENDOTHELIUM IS A TARGET ORGAN OF PARATHYROID SECRETIONS IN GENETIC HYPERTENSIVE RATS

We investigated the relationships between vascular endothelium and par athyroid function. Blood pressure (BP), circulating endothelins (ETs) and atrial natriuretic peptide (ANP), and BP responses to parathyroid hormone (PTH) and N-G-nitro-L-arginine methyl ester (L-NAME) were meas ured in parathyroidectomized (PTx), PTx and fed a Ca2+ enriched diet ( PTx-HCa) and sham SHR. 22 weeks after surgery, BP was significantly de creased in PTx and PTx-HCa, plasma ETs levels were increased, whereas ANP levels were decreased. In anesthetized rats, BP increase induced b y L-NAME was greater in PTx-HCa than in sham group, indicating increas ed endogenous nitric oxide release in hypoparathyroid rats. The hypote nsive response to PTH remained unchanged. These data demonstrate that endothelium is activated in long-term hypoparathyroid SHR, reflecting an adaptative response to decreased BP.