Further Studies on the Relationship between Potassium and Sodium Levels and Adrenocortical Activity*

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Abstract
Steroid production in vitro by dog adrenal cortical slices was measured in the presence of varying concentrations of Na and K ions. Increasing concentrations of K produced a significant increase in the intracellular K content and in the rate of synthesis of aldosterone. However, the K effect on aldosterone secretion may also occur without changes in tissue K content. Ouabain significantly diminished intracellular K content, but inhibited aldosterone production only at the high dose of 2.5 .times. 10-3 M in the presence of an elevated external K level. Physiological changes in Na concentration can modify aldosterone production. The effect was observed with changes as small as 10 meq/l Na. Changes in external K and Na levels modulate aldosterone as well as corticosterone, but not cortisol production. No changes in the intracellular content of K were detectable in angiotensin-stimulated tissue. Nevertheless, high doses of ouabain blocked angiotensin-stimulated aldosterone production without affecting cortisol production. The dissociation observed between intracellular K levels and aldosterone production suggests that there is not a simple relationship between 2 parameters.