The Renin-Angiotensin-Aldosterone System and Parathyroid Hormone Control: The RAAS-PARC Study

The RAAS-PARC study will evaluate whether angiotensin-converting enzyme inhibitors (ACEi) can lower parathyroid hormone (PTH) in normal controls and in individuals have a diagnosis of primary hyperparathyroidism. Emerging data has implicated the renin-angiotensin-aldosterone system (RAAS) activity with increased PTH. The principal investigator, and other investigators, have previously shown that inhibiting the RAAS may lower PTH. The current study will focus on: 1. Normal Physiology: Does an ACEi (which lowers angiotensin II and aldosterone) reduce PTH in normal individuals? 2. Pathophysiology: Does an ACEi reduce PTH in individuals with primary hyperparathyroidism? The results of this study may have important implications for cardiovascular and skeletal health, as both the RAAS and PTH have been implicated as mediators of these conditions.