Experimental Observations on Irradiated, Normal, and Partially Parathyroidectomized Rabbits

No significant differences were found in the reactions of irradiated, normal, or partially parathyroidectomized rabbits to injections of calcium chloride or disodium hydrogen phosphate. Intravenous injections of calcium chloride caused only a transient rise in blood calcium, which returned to its former level within a few hours. The upper level of blood calcium concentration is independent of parathyroid control. Subcutaneous injections of disodium hydrogen phosphate caused, in all three groups of rabbits, a similar depression of the blood calcium level. After large doses of the phosphate solution, all of the rabbits showed signs of acute tetany in which many of them died. Death or survival was not determined, apparently, by the absolute depression of blood calcium. The rabbits that died were those, in all three groups, in which a phosphorus retention carried the initial rise in serum phosphorus to even higher levels in the hours preceding death, and so changed the normal calcium-phosphorus ratio to a small fraction of its former value.