Phosphate Excretion Patterns Following Intravenous Injection of Ethylenediaminetetraacetate (EDTA)

Abstract

Phosphate clearance (Cp) and tubular reabsorption of phosphate (TRP) were measured before and after intravenous injections of ethylene diaminetetraacetate (EDTA). Titratable serum calcium following EDTA decreased approximately 3 mg/100 ml below control. Normal persons increased Cp and decreased percentage of TRP after injections of either EDTA or saline, but the changes following EDTA were significantly greater. Nine of 11 hyperpara-thyroid patients decreased Cp and increased percentage of TRP after EDTA, but the responses of 2 hyperparathyroid patients were similar to those of normal persons. Patients with hypoparathyroidism and pseudohypoparathyroidism also decreased Cp and increased percentage of TRP after EDTA but the changes were not as great as in hyperparathyroidism. A possible mechanism of action of EDTA in conditions of normal and of abnormal parathyroid function is presented.