Human growth hormone blunts Na2EDTA-induced hypocalcaemia in hyposomatotrophic children.

An infusion of disodium ethylenediamine tetraacetate (Na2EDTA) (0.13 mmol/kg for 2 h) was administered to 10 hyposomatotrophic children prior to and after 6 and 12 months of treatment with human growth hormone (hGH). Total and ionized calcium and immunoreactive parathyroid hormone (iPTH) concentrations were determined. Mean basal total and ionized calcium concentrations did not change during the year of treatment with hGH. The nadir concentrations of total and ionized calcium increased progressively during hGH administration and after 12 months were significantly increased over pre-treatment values (total calcium: pretreatment 1.85 +/- 0.32 (SD) mmol/l, +12 months 2.10 +/- 0.15, P less than 0.01; ionized calcium: pre-treatment 0.55 +/- 0.31 mmol/l, +12 months 0.78 +/- 0.14, P less than 0.05). The mean basal concentration of iPTH increased slightly after 12 months of hGH administration (pre-treatment 72 +/- 18 pg/ml, +12 months 106 +/- 71, P less than 0.05), but Na2EDTA-evoked secretion of iPTH was not significant altered by hGH.