PTH and vitamin D responses during treatment of hypomagnesaemic hypoparathyroidism.

The response of calcium regulating hormones in a patient with hypomagnesaemic hypoparathyroidism was assessed during magnesium infusion. Magnesium repletion was accompanied by prompt restoration of PTH secretion which subsequently stimulated 1,25-diOHD3 production, thus correcting hypocalcaemia. Further, failure of the patient to respond to previous 1 alpha-OHD3 therapy suggests that severe magnesium depletion may also result in a state of acquired resistance to the active metabolites of vitamin D.