The Effect of Cinacalcet on Gastric Acid Output in Healthy Subjects

Inclusion Criteria: * Healthy ambulatory men and postmenopausal women * Age 45 to 70 * Avoid alcohol, antacids, H2 blockers, proton pump inhibitors, or antihistamines during the study. Exclusion Criteria: * Ionized Ca++ level \<4.39 mg/dl or \>5.02 mg/dl (normal reference range 4.18- 5.02). * 24-hour UCa++ excretion \>350 mg. * Cr \>1.3. * AST/ALT values \>10% beyond reference range. * Hgb level \<11.7 g/dl in women and \<13.2 g/dl in men. * MCV level \>102 UM3. * Basal acid output \>5 mEq/h in men and \>3.8 mEq/h in women. * Basal acid output \<1 mEq/h in men and \<0.2 mEq/h in women. * Age \<45 or \>70. * Premenopausal or \<1 year post-menopause. * Individuals following vegan diets. * Current EtOH abuse. * Lidocaine allergy. Medications * Antacids * H2 blockers * Proton pump inhibitors * Carafate * Anticholinergic agents (i.e. TCA) * Cholinergic agents * Antihistamines in the last 3 weeks * Cogentin * Adrenergic blockers * Thiazide diuretics * Antiplatelet drugs * Oral and Inhaled Glucocorticoids * Bisphosphonates * Raloxifene, Tamoxifen * Tobacco * EtOH during study * rPTH * Calcitonin * Ketoconazole/Itraconazole * Calcitriol * Paricalcitol * Drisdol, Ergocalciferol * Phosphate binders * Anticoagulant * Erythromycin * Hormone replacement therapy except vaginal estrogen creams Exclusion Diseases * Achlorhydria * Pernicious anemia * Zollinger Ellison syndrome * Congestive heart failure * Esophageal strictures or motility problems * History of a GI bleed * Prior upper GI surgery * Malabsorption * History of GI malignancy * GERD, gastritis, duodenitis * Active peptic ulcer disease * Gallbladder disease * Liver disease * Pancreatitis * Current kidney stone * Renal disease * Current hypoparathyroidism or hyperparathyroidism * Moderate to Severe coronary artery disease * Aortic aneurysm * Seizure disorder * Current Arrhythmia