ExtractResponse to an exogenous calcium load was studied in 7 thyroid-treated sporadic nongoitrous cretins and in 16 normal children. An intravenous infusion of 10 mg/kg of body weight of calcium as calcium gluconate was infused over a 3-hr period. Serum samples obtained before and at 1.5, 3, 3.5, 4, 5, and 7 hr after the start of the infusion were analyzed for calcium, magnesium, and phosphorus. The base-line calcium, magnesium, and phosphorus values in serum did not differ significantly in the thyroidtreated cretins and in normal children. The infusion of calcium did not alter magnesium levels and no consistent changes were noted in phosphorus levels in either group. Mean increments in calcium levels, however, were significantly greater in the cretins at 1.5, 3, 3.5, and 4 hr after the start of the infusion. The response to calcium infusion in two children with a thyroid-iodine organification defect was similar to that seen in the normal children.
Speculation