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Digoxin‐associated decrease in parathyroid hormone ( PTH ) concentrations in patients with atrial fibrillation
Author(s) -
Apel Arie,
Rachel Pauzner,
Cohen Ohad,
Mayan Haim
Publication year - 2013
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/eci.12026
Subject(s) - medicine , endocrinology , digoxin , parathyroid hormone , calcium metabolism , verapamil , chemistry , homeostasis , calcium , heart failure
Background Parathyroid hormone ( PTH ) secretion is regulated mainly by the calcium sensor receptor. Recently, other components of calcium homoeostasis have been revealed, namely the effect of K lotho on stimulation of PTH secretion by the recruitment of N a‐ K ‐ ATP ase and by its being a cofactor in the inhibitory effect of FGF 23 on PTH secretion. It seems that ouabain, a N a‐ K ‐ ATP ase inhibitor, prevents the increase in PTH secretion in a hypocalcemic environment, as observed in mouse and bovine tissues. We hypothesized that digoxin, which is similar to ouabain in its effect on the sodium pump, might decrease PTH levels in humans. Methods Twenty patients with atrial fibrillation were studied. Ten patients were treated with digoxin and the other ten patients with verapamil. Baseline chemistry parameters were determined and 0·25 mg digoxin injected. Plasma PTH concentrations, ionized calcium concentrations and digoxin levels were recorded at 30 min, 1 h, 2 h and 4 h postinjection. Results Baseline blood parameters were similar in both groups. In the control group plasma PTH concentrations increased, whereas in the digoxin group, they decreased. Ionized calcium concentrations did not change over time in either groups. There seemed to be blunting of the circadian rhythm of PTH levels in the morning hours. Conclusions Although the patients were normocalcemic, plasma PTH concentrations decreased with digoxin treatment. The effect of the sodium pump on PTH secretion might be important in human PTH homoeostasis and might be a potential target for the treatment of disturbances in calcium homoeostasis.