PARATHYROID-HORMONE SECRETION AND RESPONSIVENESS TO PARATHYROID-HORMONE IN PRIMARY HYPOMAGNESEMIA

  • 1 January 1983
    • journal article
    • research article
    • Vol. 19  (4) , 345-348
Abstract
Parathyroid function was studied in 2 infant sisters with primary hypomagnesemia while they were both hypomagnesemic and hypocalcemic. In one of the infants, plasma immunoreactive parathyroid hormone (iPTH) was elevated, the calcemic response to exogenous PTH was absent and the phosphaturic response was normal. Restoration of serum Mg with i.v. Mg corrected the hypocalcemia, with no further rise of plasma iPTH. In the other infant, plasma iPTH was undetectable, and exogenous PTH produced both phosphaturic and calcemic responses. Normalization of serum Mg with i.v. Mg resulted in a prompt release of endogenous PTH and correction of the hypocalcemia. In the 1st patient, hypocalcemia was apparently associated with lack of response of the bone to both endogenous and exogenous PTH, while in the 2nd patient, hypocalcemia was associated with inhibition of PTH release and a normal calcemic response to exogenous PTH. The factors that determine whether Mg deficiency will result in inhibition of PTH release, in a lack of response of the bone to endogenous and exogenous PTH, or both, remain to be clarified.