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

Inclusion Criteria: * Healthy subjects with with no medical problems (n=15) and individuals with primary hyperparathyroidism (n=30) * normal blood pressure or stage 1 hypertension that is either untreated, or adequately treated with a single anti-hypertensive medication. * Age \>18 years and \<80 years * Estimated GFR \> 60ml/min Exclusion Criteria: * Chronic Kidney Disease or eGFR\<60 * Stage 2 or Stage 3 hypertension or the use of more than 1 antihypertensive drug * Type 2 Diabetes Mellitus that is not controlled by diet or Metformin alone or with a Hemoglobin A1c \>7.5% * History of liver failure * History of heart failure * The use of typical or atypical antipsychotic medications or lithium. * Chronic inflammatory conditions (such as inflammatory bowel disease or arthritis) that are treated with prescribed doses of NSAIDs or glucocorticoids * The use of prescribed doses of potassium supplements. * Illness requiring overnight hospitalization in the past 6 months * Active tobacco or recreational drug use * Pregnancy or current breast feeding