1. Balance studies have been made on three dogs before and after
adrenalectomy, performed in two stages. 2. It has been shown that the
sodium concentration of the blood decreases in adrenalectomized dogs, as is true in patients suffering from
Addison's disease and in cats experimentally adrenalectomized. 3. There are also decreases in the
chloride and
bicarbonate concentrations which together are approximately equivalent to the decrease in
sodium. 4. An increase in the
potassium concentration of the blood occurs after
adrenalectomy, as reported in other studies. There is no obvious correlation of this change with changes in
potassium balances. 5. The balance studies show a striking loss of
sodium from the body during the development of
adrenal insufficiency. This loss of Na results from an increased excretion of
sodium in the urine and is not complicated by loss of base as a result of
vomiting or
diarrhea. 6. Following
adrenalectomy, both the total amount of
sodium and its concentration in the urine are markedly increased. This increase in concentration of
sodium occurs in spite of an augmented urine volume. 7. The behavior of the
chloride ion following
adrenalectomy parallels that of the
sodium ion, but the loss is not equivalent. 8. During the period of accumulation of non-
protein nitrogen in the blood, the rate of water excretion by the kidney is even greater than before removal of the adrenal glands. 9. The possibility of a regulatory effect of the adrenal glands upon
sodium metabolism and renal function has been discussed.