Excretion and retention of cadmium, zinc, and mercury by rabbit kidney.

FOULKES, E. C. Excretion and retention of cadmium, zinc, and mercury by rabbit kidney. Am. J. Physiol. 227(6) : 1356-1360. 1974.Mean renal artery-to-vein transit times (Z) of logCd, 65Zn, or zo3Hg were compared to those of Evans blue (EB) and inulin in rabbits. All three klements were fully recovered in venous plasma, where they slightly preceded inulin, although 7 exceeded &. Competition for the injected metals is suggested between circulating plasma protein and fixed endothelial ligands. Upon addition of mercaptoethanol (ME) to the bolus injection, logCd appeared in urine; total recovery in blood and urine dropped to two-thirds of the dose reaching the kidney. Renal retention of the remaining one-third was reduced by 30 yO after ureteral occlusion. Both luminal and peritubular cell membranes thus are involved in Cd uptake, a conclusion in agreement with the previous finding of lesions at those two sites. jn the presence of ME, essentiallyall z*3Hg was retained in the kidney but renal handling of Zn was not affected. The stronger chelator EDTA led to recoveries of logCd in blood and urine approaching those of inulin. These results bear on the role of metal ligands in determining renal excretion and accumulation of heavy metals.