EFFECTS OF ETHACRYNIC ACID ON RENAL UPTAKE OF MERCURY

¹ Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan

Movement of mercury, added as chlormerodrin-Hg²⁰³ to a phosphate incubation medium, into renal cortical slices of rat and dog is an active process; it is retarded by lowering temperature of incubation to 4°C or by anoxia. Slices of rat renal medulla also actively accumulate mercury but terminal segments of the proximal tubules are included in the slices. Direction of transport (i.e., "reabsorptive" or "secretory") is unknown.

Ethacrynic acid, a compound which reacts with renal sulfhydryl groups, reduces uptake of mercury into viable and nonviable slices of renal cortex of the dog and rat.

Entrance of mercury into slices of renal cortex, renal medulla, and liver, in which proteins have been inactivated by trichloroacetic acid, is reduced when ethacrynic acid is added to incubation media containing the above tissues.

The data indicate that ethacrynic acid inhibits active transport of chlormerodrin into renal cortical slices and also reacts chemically with the same tissue constituents (presumably protein-bound sulfhydryl groups) with which the mercurial normally reacts. Thus the mechanism of action of these diuretic agents may be similar.