ALDOSTERONE EXCRETION IN NORMAL SUBJECTS DEPLETED OF SODIUM AND POTASSIUM 1

Abstract

An inverse relationship has previously been shown between Na intake and aldosterone excretion in man. The effect of K deprivation on the urine output of aldosterone was investigated in 3 healthy men during normal and reduced Na intake. Urinary and plasma electrolytes, creatinine, and urinary corticosteroids were measured. A marked decrease in aldosterone output below control values of 1.4, 1.5, and 1.9 [mu]g/24 hours was observed after 10 days on a K intake of 9 meq per day and 145 meq Na intake. In all 3 subjects at this time, aldosterone output reached such low levels as not to be detectable with certainty. When Na intake was also reduced to 9 meq, aldosterone output rose to levels 2 to 6 times the original control values after about 7 days. This increase in aldosterone output was slower and did not reach as high levels as previously observed following Na deprivation alone. Restoration of K to the diet during continued low Na intake was followed by a further increase in aldosterone output to 9.6, 11.5, and 8.9 [mu]g/24 hours in these subjects. The highest observed output of aldosterone in one subject was during administration of 150 meq ammonium chloride for 2 days, before K replacement. Insignificant changes were observed in the output of 17-ketosteroids and 17-hydroxycorticosteroids.