Activation of the calcium sensing receptor stimulates gastrin and gastric acid secretion in healthy participants.
In 17 adults on a fixed metabolic diet, an 11-day course of cinacalcet increased serum gastrin and basal gastric acid output, but not maximal gastric acid output, compared with a placebo. These findings indicate that the calcium sensor receptor plays a role in the regulation of gastric acid.


BACKGROUND
Gastric acid secretion is a complex process regulated by neuronal and hormonal pathways. Ex vivo studies in human gastric tissues indicate that the calcium sensing receptor (CaR), expressed on the surface of G and parietal cells, may be involved in this regulation. We sought to determine whether cinacalcet, a CaR allosteric agonist, increases serum gastrin and gastric acid secretion.


METHODS
Seventeen healthy adults with normal gastric acid output were placed on an 18-day metabolic diet. On day 8 (baseline), participants were given cinacalcet (15 then 30 mg/day) or placebo for 11 days. Changes in gastric acid output, serum gastrin, and other measures were compared in the two groups.


RESULTS
Changes in serum gastrin and basal acid output (adjusted for baseline body weight) were significantly more positive in the cinacalcet group compared with placebo (P = 0.004 and P = 0.039 respectively). Change in maximal acid output was similar in the two groups (P = 0.995). As expected, cinacalcet produced significant decreases in serum PTH (P < 0.001) and ionized calcium levels (P = 0.032), and increases in serum phosphorus levels (P = 0.001) and urinary calcium (P = 0.023).


CONCLUSIONS
This study provides in vivo evidence that activation of the CaR increases serum gastrin levels and basal gastric acid secretion in healthy adults.
Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA, 02111, USA, lisa.ceglia@tufts.edu.
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Rasmussen
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Dawson-Hughes
D000704:Analysis of Variance; D002118:Calcium / Q000097:blood / Q000378:metabolism / Q000652:urine; D000069449:Cinacalcet; D003404:Creatinine / Q000652:urine; D005260:Female; D005744:Gastric Acid / Q000737:chemistry / Q000378:metabolism*; D005750:Gastric Juice / Q000737:chemistry; D005753:Gastric Mucosa / Q000378:metabolism*; D005755:Gastrins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008274:Magnesium / Q000652:urine; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000494:pharmacology*; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D044169:Receptors, Calcium-Sensing / Q000187:drug effects / Q000378:metabolism*; D013268:Stimulation, Chemical
D005755:Gastrins; D009281:Naphthalenes; D010281:Parathyroid Hormone; D044169:Receptors, Calcium-Sensing; D010758:Phosphorus; D003404:Creatinine; D008274:Magnesium; D002118:Calcium; D000069449:Cinacalcet