The mechanism of renal transport and excretion of ethylenediaminetetraacetate with interspecies comparisons

The renal transport and excretion of ethylenediaminetetraacetate (EDTA) was studied by conventional steady-state techniques in conscious dogs, calves, and rats. Concentrations of 250–400 μ m EDTA were maintained in the plasma during the period of study. The average ratio C EDTA/C inulin measured for the 3 species ranged from 0.94 to 0.97. The clearance ratio was unaffected by alterations in urine pH or rate of urine flow or by the administration of p-aminohippurate (PAH), probenecid, or N 1 -methyl nicotinamide. The intravenous injection of CaEDTA, producing initial plasma concentrations in excess of 1 m m, did not affect the renal clearance of either EDTA or inulin. Likewise, the administration of PAH was without effect on the distribution volume of EDTA in the body or its rate of disappearance from the plasma. The data indicate that the mechanism for the renal excretion of EDTA is glomerular filtration.