Role of the kidney in potassium homeostasis: Lessons from acid-base disturbances

Abstract

Potassium homeostasis in man is normally accomplished by appropriate changes in the renal excretion of this cation in response to random variations in intake. Although this physiologic feedback system normally functions to maintain potassium balance well within tolerable limits, it has long been known that potassium excretion can be influenced importantly by numerous factors unrelated to total body potassium content [1]. A detailed understanding, however, of the interaction between the interests of potassium homeostasis and the constraints imposed by other physiologic priorities remains to be defined. A highly promising focal point for further investigation into the renal regulation of potassium balance has emerged recently from experimental observations using renal micropuncture techniques; these observations have provided major new insights into the nature of the tubular mechanisms through which the many diverse influences on renal potassium excretion operate [2]. The purpose of this editorial is to utilize these new insights in an attempt to explain the well-documented effects on potassium excretion that stem from the common disturbances of acid-base equilibrium. In so doing, it is hoped that a better understanding will emerge not only of the interplay among the numerous factors impinging on renal potassium handling, but also of the renal adaptive mechanisms called into play by persistent acid-base disorders.