THE RENAL EXCRETION OF SODIUM AND WATER BY RATS DURING INFUSION OF HYPO-, ISO- AND HYPERTONIC SALINE

¹ The Department of Medicine, University of Durham, The Medical School, Newcastle upon Tyne, 1, England

1. The renal excretion of sodium and water by unanæsthetized rats has been studied, while a continuous intravenous infusion of hypo-, iso- or hypertonic saline was given. The experiments were continued for eight hours.

2. In all cases the rates of excretion of water and sodium increased during the first two hours, and the renal tubular reabsorption of the two substances fell. Glomerular filtration rate increased initially but fell later, although sodium and water excretion remained high throughout.

3. These findings have been discussed and a tentative hypothesis offered involving volume and osmoreceptor/ADH function, decreased production of sodium-retaining steroid, and the interaction of these changes on the kidney.