Primary Outcome Measures:
- 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. [ Time Frame: 11 days ]
Secondary Outcome Measures:
- Compare serum gastrin levels in subjects before and after an 11-day course of cinacalcet or placebo and on a fixed protein metabolic diet. [ Time Frame: 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. [ Time Frame: 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. [ Time Frame: 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. [ Time Frame: 11 days ]
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.