Effect of Ethylenediaminetetraacetic Acid on Radiostrontium Excretion in Man.

Abstract

The effect of ethylenediamine-tetraacetic acid (Na-EDTA) on S85 excretion was studied in three patients under controlled metabolic conditions. A decrease of urinary Sr85 excretion to less than half the amount of the control excretion was noted on the days of Na-EDTA infusions. Following the dis-continuation of the Na-EDTA infusions the urinary Sr85 increased considerably and this excess compensated for the inhibition of Sr85 excretion on the experimental days. It is suggested that the mechanism of decreased radiostrontium excretion involves competition between ionic Ca and Sr at the renal tubular level and that chelation of Ca favors Sr reabsorption due to decreased excretion of ionized Ca. The fecal Sr85 excretion remained unchanged in the experimental phase.