The Effects of Alterations of Plasma Sodium and Potassium Concentration on Aldosterone Secretion*

Abstract

Mlany studies have been conducted on the relation of electrolytes to the control of aldosterone secretion. It was reported by Luetscher and Axelrad (1) and confirmed by others (2-4) that a low Na intake augments the rate of urinary aldosterone excretion in normal man. Also, it has been clearly established that chronic Na depletion increases aldosterone secretion in sheep (5, 6), dogs (7,8), and rats (9). On the other hand, the relation of K intake to aldosterone production has never been settled. Several investigators (2, 3, 10) have reported that K loading leads to hyperaldosteronuria; the response was observed only in the presence of a low Na intake or was greater with a reduced intake of salt. In contrast, Hernando and associates (4) failed to find an increase in urinary aldosterone output during K loading even in the presence of a superimposed low Na intake.The influence of hyperkalemia and of hyponatremia has also been a controversial issue. Laragh and Stoerk (10) were first to report that a high plasma K concentration increases aldosterone secretion. Later, Moran. Rosenberg, and Zimmerman (11) presented data which suggested that intravenous infusion of KCl into intact dogs increased aldosterone secretion, but Gann, Cruz, Casper. and Bartter (12) were unable to confirm this finding. Denton, Goding, and Wright (5) provided evidence that a low Na and high K concentration in plasma perfusing an isolated adrenal stimulates aldosterone production in sheep; also, some of their more recent findings (6) suggest that this directional alteration in either ion alone augments aldosterone secretion. * Preliminary report was made at the meeting of the Federation of American Societies for Experimental Biology, April, 1962. The present observations were undertaken to determine the separate influences of 1) a decrease in plasma Na concentration and 2) an elevation in the plasma K level on aldosterone secretion. As emphasized previously (13,14), it is frequently important for acute studies in laparotomized dogs to be conducted in hypophysectomized animals because of the influence of ACTH which is present in increased amounts in stressed animals. Studies were first conducted on the effects of intravenous infusion of a K salt on aldosterone secretion in hypophysectomized dogs. Subsequently, the influence of acute bilateral nephrectomy on the hypersecretion of aldosterone induced by hyperkalemia was determined. The possible direct effect of either a low plasma Na or a high plasma K concentration on the adrenal cortex was examined by producing local alterations in these ions in arterial blood perfusing isolated adrenals. Finally, the physiological significance of alterations in K intake on aldosterone production was investigated by studying the response to a high K intake. The plasma K concentration and the rate of urinary aldosterone excretion were observed for several hours following the daily meal during which a progressive elevation in the plasma K concentration occurred during the high K diet. MATERIALS AND METHODSIittra...

Ectopic pinealoma with adipsia and hypernatraemia.

“…The cells of the juxtaglomerular apparatus may function as osmoreceptors (Fisher et al, 1965). There is experimental evidence that aldosterone secretion is decreased when the plasma sodium concentration is raised experimentally (Coghlan et al, 1960;Davis et al, 1963), but no information appears to be available for man. Our patient may demonstrate the human counterpart of these experiments.…”

Modulation of Plasma Aldosterone Concentration by Plasma Potassium in Anephric Man in the Absence of a Change in Potassium Balance

“…Previous studies have shown that aldosterone production can be markedly influenced by changes in potassium ( [1][2][3][4][5]. It is still uncertain, however, whether the modulating effect of potassium is dependent upon gross changes in potassium balance or whether it may also occur in response to changes in plasma potassium concentration independently of changes in potassium balance.…”

“…However, studies by Dluhy, Axelrod, Underwood, and Williams have shown that plasma aldosterone concentration can be increased acutely by intravenous potassium administration regardless of the previous dietary potassium intake (7). Similarly, aldosterone secretion by the isolated adrenals of dogs (3) and sheep (8) PRA in preinfusion blood samples were determined by a modification of the radioimmunoassay described by Haber, Koerner, Page, Kliman, and Purnode (11). Plasma aldosterone concentration was determined by a modification of the radioimmunoassay described by Bayard, Beitins, Kowarski, and Migeon (12) utilizing ammonium sulfate precipitation of bound antigen in the assay as described by Mayes, Furuyama, Kem, and Nugent (13).…”

The influence of potassium administration and of potassium deprivation on plasma renin in normal and hypertensive subjects

“…From the Department of Medicine, Columbia University, College of Physicians and Surgeons and the Presbyterian Hospital in the City of New York, New York 10032 A B S T R A C T The effect of potassium administration and of dietary potassium deprivation on plasma renin activity and aldosterone excretion has been studied in 10 normal subjects and in 12 hypertensive patients maintained on a constant dietary regimen.…”

“…Potassium administration and changes in potassium balance also exert a potent influence on aldosterone secretion (8)(9)(10)(11)(12)(13). Perfusion studies in animals have indicated that changes in plasma K+ act directly on the adrenal cortex to increase aldosterone secretion (11).…”