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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #211367
Title: Activation of the calcium sensing receptor with cinacalcet increases serum gastrin levels in healthy older subjects

Author
item CEGLIA, LISA - TUFTS/HNRCA
item HARRIS, SUSAN - TUFTS/HNRCA
item RASMUSSEN, HELEN - TUFTS/HNRCA
item Dawson-Hughes, Bess

Submitted to: American Society for Bone and Mineral Research
Publication Type: Abstract Only
Publication Acceptance Date: 6/15/2007
Publication Date: 9/15/2007
Citation: Ceglia, L., Harris, S.S., Rasmussen, H., Dawson-Hughes, B. 2007. Activation of the calcium sensing receptor with cinacalcet increases serum gastrin levels in healthy older subjects. In: ASBMR Annual Meeting, 9/16/2007-9/19/2007, Honolulu, Hawaii.

Interpretive Summary:

Technical Abstract: Gastric acidity is postulated to enhance calcium absorption since calcium is better dissolved at low pH. Extracellular calcium stimulates gastrin and gastric acid secretion in humans. Ex vivo studies indicate that the calcium sensing receptor (CaR), which is expressed on the surface of human G cells and parietal cells, may be involved in this regulation. We evaluated whether cinacalcet (C), a CaR agonist, compared to placebo (P) would increase serum gastrin level (G) and basal gastric acid output (BAO) in healthy subjects.17 subjects age 47-70 were placed on a metabolic diet with fixed protein, calcium, phosphorus, sodium, magnesium, potassium, and vitamin D for 18 days. We measured G, BAO, intact parathyroid hormone (PTH), and 24-hr urine calcium-to-creatinine excretion ratio (Ca/Cr) at baseline (day 8, following a run-in period) and post-intervention (day 18). C was titrated to 30 mg daily. G was measured by the Diasorin method. Gastric volume, pH and acid mEq were measured to calculate BAO. Mean G was similar in the 2 groups at baseline (C = 33.1 +/- 13.9 (SD) pg/ml (n=9), P = 38.5 +/- 13.9 pg/ml (n=8)). However, mean change in G differed (C = 7.0 +/- 7.3 pg/ml, P = -4.6 +/- 6.8 pg/ml, p = 0.004). Mean BAO at baseline was similar in the 2 groups (C = 2.14 +/- 1.77 mEq/hr, P = 2.43 +/- 1.56 mEq/hr), and mean change in BAO did not differ significantly (C = 1.32 +/- 2.37 mEq/hr, P = -0.24 +/- 1.08 mEq/hr, p = 0.109). In the group as a whole, change in G correlated with change in BAO (r = 0.530, p = 0.029 (n=17)). Baseline mean PTH was similar in the 2 groups (C = 43.9 +/- 16 pg/ml, P = 47.8 +/- 18.0 pg/ml), and as expected mean change in PTH differed (C = -26.9 +/- 11.7 pg/ml, P = 14.3 +/- 17.0 pg/ml, p = <0.0001). Ca/Cr did not differ significantly at baseline in the 2 groups (C = 84.9 +/- 59.9 mg/g, P = 114.3 +/- 80.1 mg/g), but mean change in Ca/Cr was significantly different (C= 17.9 +/- 24.6 mg/g, -12.2 +/- 24.3 mg/g, p = 0.023). These results show that activation of the CaR with cinacalcet stimulates gastrin secretion, and that an increase in gastrin is associated with a rise in basal gastric acid output in healthy older subjects. The impact of these changes on calcium absorption requires further investigation.