RENAL ACTION OF MERCURIAL DIURETICS AS AFFECTED BY SODIUM LOAD’

Duggan and Pitts (1950) claim that in the dog mercurial diuretics in maxi-mally tolerated doses and under high saline loads depressed tubular reabsorption of sodium by about 1.5 to 1.7 milliequivalents of sodium per minute. This de-pression of sodium reabsorption is about 21 per cent of the sodium filtered. Since this value corresponded to the postulated facultative reabsorption occur-ring in the distal tubular apparatus (Wesson, Anslow and Smith, 1948), Duggan and Pitts have suggested that the site of action of mercurial diuretics was in the cells of the distal renal tubule. Mudge, Foulks and Gilman (1949), on the other hand, working under somewhat different experimental conditions, have found in a limited number of experiments depression of sodium reabsorption equal to 25 to 28 per cent of the sodium filtered. They suggested an action of mer-curial diuretics on the proximal tubular mechanism. In the present study we have investigated the influence of dosage of mercury and saline load on the renal action of mercurial diuretics. METHODS: The mercurials employed were mersalyl3 (2-[(2-hydroxy-mercuri-3-methoxy-propyl) carbamyl] phenoxy acetic acid) and Esidron Acid4 (2-[2-hydroxy-mercuri-3-hy-droxy-propyl-carbamyl] nicotinic acid). Both compounds were given with cysteine (1:1 molar ratio) since, in many instances, cardio-toxic quantities of these mercurials had to be injected. Cysteine protects the heart but does not interfere with the diuretic effects of these mercurials (Farah and Iaresh, 1948)