THE ACTION OF POTASSIUM SALTS ON THE ISOLATED KIDNEY OF THE DOG

¹ Department of Pharmacology, University of Kansas School of Medicine, Kansas City, Kansas

1. The diuretic action of potassium nitrate and of potassium chloride was studied in eight experiments on dogs, in which the kidney was isolated, and perfused by means of the heart-lung preparation.

2. In this type of experiment there is normally some diuresis, accompanied by a marked decrease in the concentration of urinary solids. Nevertheless, administration of the potassium salts was followed in most instances by a greater diuresis; also, by a simultaneous increase in the urinary concentration and output of potassium, chloride, sodium, and urea.

Moreover, in the experiments in which there was relative failure of the kidney to concentrate and excrete the injected potassium salts, there followed a correspondingly low urinary concentration and output of chloride, sodium, and urea.

3. These observations on the isolated kidney agree with results of other experiments cited on intact dogs and in man, which further demonstrate the capacity of potassium salts to increase the urinary excretion of potassium, chloride, and sodium. They are also similar to the effects of caffeine on the heart-lung-kidney preparation, reported by Verney and Winton.

4. There may be unknown "extra-renal" factors which play a part in the renal function of a heart-lung-kidney preparation. The evidence suggests, however, that the diuretic action of potassium salts is effected chiefly through direct influence on the kidney.