EXPERIMENTAL POTASSIUM DEPLETION IN NORMAL HUMAN SUBJECTS. I. RELATION OF IONIC INTAKES TO THE RENAL CONSERVATION OF POTASSIUM*

Abstract

Eleven normal male subjects were depleted of K for 6 to 21 days in 14 balance studies in which the K intakes were set at one of three intake levels: 25 to 27 meq, 14 to 16 meq, or < 1 meq/day. The effect of various dietary programs (high and low Na intakes, variation in acidity of the diet, and prior loading with K) On the urinary and fecal losses of K were studied. Fecal K accounted for 11 to 59% of the total loss of K when the intake of K was less than 1 meq/day. The largest K deficit was 502 meq, attained in 21 days on the <1 meq/day intake. The rate of urinary excretion of Na on a low Na intake was diminished when the concomitant K intake was low. Metabolic alkalosis was an inconstant finding and when present was of a minor degree. It was concluded from all the data of the studies (1) that the degree of renal conservation of K (a) is related to the degree of change in intake of the ion from pre-deprivation levels and to the duration of the deprivation, (b) is diminished by an increased intake of Na, and (c) is less efficient than the renal conservation of Na under conditions of comparable deprivation of the respective ions; (2) that with prolonged deprivation of K the fecal loss of the ion, though absolutely decreasing, becomes a progressively larger factor in the development of the negative K balance; and (3) that a marked degree of extracellular metabolic alkalosis is not an obligatory accompaniment to K depletion of the normal human subject.