EFFECT OF ALDOSTERONE AND CORTISOL ON SODIUM AND WATER CONTENT OF THE RAT KIDNEY.

The present studies were undertaken to determine the effect of aldosterone and cortisol on the sodium content of the kidney. Rats were injected intraperitoneally with 50 µg of d -aldosterone or 100 µg of d , l -aldosterone, or with 2 mg of cortisol. Three to four hours later the kidneys were removed and analyses of sodium and water in the papilla, medulla, and cortex were performed. Aldosterone in both normal and adrenalectomized animals and cortisol in adrenalectomized animals increased the sodium concentration in the wet tissue, tissue water, and tissue solids in all areas of the kidney. Papillary sodium and cortical water were reduced in the adrenalectomized animals. Cortisol, in addition to its effects on sodium, restored cortical water to levels observed in normal control animals, while aldosterone had no influence on water in any area of the kidney. The magnitude of increase of sodium in the tissue solids of the cortex was greater with aldosterone than with cortisol.