RENAL ACTION OF MERCURIAL DIURETICS AS AFFECTED BY SODIUM LOAD

¹ Department of Pharmacology and Medicine, University of Washington, Seattle, Washington
² Department of Pharmacology, State University of New York, Medical Center at Syracuse University, Syracuse, N. Y.

The effect of the dosage of mercurial diuretics under high sodium load has been determined. Four to six mgm. of mercury per kgm. produce maximal effects on renal sodium reabsorption. Under our experimental conditions there were no quantitative or qualitative differences in the action of mersalyl and Esidron acid on renal sodium reabsorption.

Isotonic sodium chloride infusions increased the response to mercurial diuretics. This is partially due to the increased sodium load on the kidney. The effects of mercurial diuretics on sodium reabsorption were determined by the rate of infusion of isotonic saline. At the highest rates of infusion of saline used, a maximal dose of mercurial produced a depression of 5 to 6 milliequivalents per m² per minute in the renal reabsorption of sodium. This corresponds to about 35 to 40 per cent of the sodium filtered.

If distal tubular sodium reabsorption accounts for about 20 per cent of the filtered sodium load the effects of mercurials on sodium reabsorption cannot be explained by an action on the distal tubular mechanism for sodium reabsorption.