AN ATTEMPT TO REPRODUCE EXPERIbfENTALLY THE PLQTTERN OF SALT AND WATER DISTRIBUTION OF AGE IN THE YOUNG NEUROMYPOPfIYSECTOhf IZED ,QDRENALECTOhfIZED RAT1

Previous studies of the illteractiori of aldosterone, vasopressin, and corticosterone in ths ncurohypophysectornized adrenalectomized rat suggested that the salt and water distribution patten1 in the muscles of the ageti rat and that observed in simple aldosterone domiriance were similar. 'I'his was tested by mainta.iiiing youug ~leurohypo~)hysectolllized adrenalectornixed rats with aldosterone alone for 2 xnollths and cormparing the resulting pattern with that of old rats, 27 months of age. Changes identical with those which occur spontaneously in the aged muscle, although of lesser degree, were reproduced in the young aninlals. Thus, total muscle sodillin increased in association with a ~orresp~rldiilg loss of potassium and a shift of water from cells to environment. ,As in the old :r~iinlais, an illcrease iii total muscle water Ivas observed.