Journal ArticleDOI
Extrarenal potassium homeostasis
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TLDR
Hormonal regulation, cellular shifts of potassium are influenced by changes in acid-base balance, and uremia-related changes are discussed in the context of the present understanding of normal extrarenal potassium metabolism.Abstract:
Normal potassium homeostasis is regulated by both renal and extrarenal mechanisms. Although chronic potassium balance is primarily regulated by the kidneys, acute potassium tolerance is largely determined by extrarenal tissues. During the first 4-6 h following an acute potassium load, only about 50% of the potassium is excreted by the kidneys. Of the remaining 50% that is retained, over 80% is translocated into cells, and this provides the primary defense against hyperkalemia. Potassium uptake by both liver and muscle and intestinal secretion of potassium are the most important mechanisms of extrarenal potassium disposal. Several hormones, including insulin and epinephrine, have been shown to play an important role in the maintenance of normal extrarenal potassium metabolism. These hormones function by enhancing potassium uptake by liver and muscle. There is also evidence that aldosterone is necessary in the maintenance of normal extrarenal potassium tolerance. Although the major extrarenal site of action of aldosterone has not yet been clearly defined, gastrointestinal potassium secretion and muscle transport of potassium are both affected by the hormone. Evidence exists that glucocorticoids may also have an effect on extrarenal potassium homeostasis. In addition to this hormonal regulation, cellular shifts of potassium are influenced by changes in acid-base balance. Extrarenal potassium tolerance is impaired in chronic renal insufficiency. These uremia-related changes are discussed in the context of our present understanding of normal extrarenal potassium metabolism.read more
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Journal ArticleDOI
Dynamics and Consequences of Potassium Shifts in Skeletal Muscle and Heart During Exercise
Ole M. Sejersted,Gisela Sjøgaard +1 more
TL;DR: It is concluded that despite modifying factors coming into play during muscle activity, the K(+) shifts with high-intensity exercise may contribute substantially to fatigue in skeletal muscle, whereas in the heart, except during ischemia, theK(+) balance is controlled much more effectively.
Journal ArticleDOI
Hormonal regulation of the Na(+)-K(+)-ATPase: mechanisms underlying rapid and sustained changes in pump activity
H. S. Ewart,A. Klip +1 more
TL;DR: This review assesses the acute and long-term actions of a number of hormones (aldosterone, thyroid hormone, catecholamines, insulin, carbachol) on the Na(+)-K+ pump and finds that in some tissues the rapid action of insulin, aldosterone, andcarbachol involves changes in the subcellular distribution of pump units.
Journal ArticleDOI
Plasma potassium changes with high intensity exercise.
TL;DR: The large, rapid changes in the plasma potassium concentration during and after exercise is due to the first order kinetics of the reuptake mechanism rather than to a limited power to take up potassium.
Journal ArticleDOI
Effect of various therapeutic approaches on plasma potassium and major regulating factors in terminal renal failure
TL;DR: In patients with terminal renal failure undergoing maintenance hemodialysis, intravenous bicarbonate is ineffective in lowering plasma potassium rapidly, and epinephrine is effective in only half the patients, whereas insulin in glucose is a fast and reliable form of therapy for hyperkalemic emergencies.