The Defense against Hyperkalemia: The Roles of Insulin and Aldosterone

POTASSIUM homeostasis can be conveniently divided into two inter-related systems: external and internal potassium balance. External balance controls total body potassium content and is determined by the difference between potassium intake and potassium excretion. Since potassium losses in the stool and sweat are normally relatively small, renal excretion is the dominant factor that usually determines external potassium balance. In certain kinds of intestinal disorders, however, diarrhea or malabsorption may lead to very large stool losses, but, normally, intestinal excretion plays little or no part in the defense against hyperkalemia. Internal balance refers to the distribution of potassium between the extracellular . . .