The Effect of Cinacalcet on Gastric Acid Output in Healthy Subjects

Study Overview
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Brief Summary
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The purpose of this study is to determine whether cinacalcet will increase gastric acid secretion in healthy volunteers.

Detailed Description
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The calcium sensing receptor (CaSR) was originally found on parathyroid and renal cells and more recently it has been identified on cells that regulate gastric acid secretion (G cells and parietal cells). However, its role in regulating acid secretion in humans is completely unknown and is of potential importance because an acid environment in the stomach enhances intestinal calcium absorption. In this pilot project, we will stimulate the CaSR with a CaSR-agonist called cinacalcet. Our hypothesis is that activation of the CaSR will in turn increase gastric acid production in healthy volunteers.

Conditions
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Healthy

Intervention / Treatment
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* Drug: cinacalcet


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 45 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Intervention/Treatment |
| --- |
|Drug: cinacalcet|nan|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Compare change in gastric acid output in response to an 11-day course of daily cinacalcet or placebo in subjects on a fixed protein metabolic diet. |  | 11 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Compare serum gastrin levels in subjects before and after an 11-day course of cinacalcet or placebo and on a fixed protein metabolic diet. |  | 11 days | 
| Compare 24-hour urinary calcium excretion before and after an 11-day course of cinacalcet or placebo and on a fixed protein metabolic diet. |  | 11 days | 
| Compare serum IGF-1 levels before and after an 11-day course of cinacalcet or placebo and on a fixed protein metabolic diet. |  | 11 days | 
| Compare change in urinary magnesium excretion in response to an 11-day course of daily cinacalcet or placebo in subjects on a fixed protein metabolic diet. |  | 11 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gastric acidity determination, Calcium sensing receptor