THE EFFECTS OF CALCIUM DISODIUM ETHYLENEDIAMINE TETRAACETATE ON URANIUM POISONING IN RATS

¹ Division of Pharmacology and Toxicology, Department of Radiation Biology, University of Rochester, School of Medicine and Dentistry, Rochester, New York

The toxicity of single intraperitoneal doses of Ca EDTA was found to be low in young adult female albino rats (Rochester-Wistar strain); the LD₅₀ was 3.8 gm./kgm. (s.e._LD5O ±0.08).

Intraperitoneal injections of 50 mgm. Ca EDTA/rat at 2,4, and 6 hours during a 24 hour feeding period with diets containing 4 or 8 per cent, respectively, of uranyl nitrate hexahydrate reduced the mortality. Two injections of Ca EDTA at 2 and 6 hours, or single injections at 4 hours or at 24 hours were ineffective.

Given intraperitoneally as a solution of uranyl nitrate, the 30 day LD₅₀ for rats was 3.2 mgm. U/kgm. (s.e._LD5O ±1.1); the 30 day LD₅₀ for Ca EDTA-treated rats (intraperitoneal doses at 2, 4, and 6 hours) was 9.3 mgm. U/kgm. (s.e.LD5O ± 1.5). Ca EDTA counteracted three lethal doses of uranium.

Ca EDTA increased the 24 hour urinary excretion of parenterally administered uranium by approximately 50 per cent whether the Ca EDTA was given as one injection (simultaneously) or as three injections (simultaneously, at 4, and 6 hours). The excretion of uranium in both control and treated rats was negligibly small during the second and third 24 hour periods.

Ca EDTA did not mobilize uranium deposited in the skeleton; femurs of Ca EDTA treated and control rats contained equal amounts of uranium.