Potassium ion concentration in extracellular fluid

The potassium ion concentration in extracellular fluid refers to the precise amount of potassium ions (K^+) present outside cells in body fluids, particularly in plasma and interstitial fluid. Normally, potassium is the major intracellular cation, with only about 2% found in the extracellular compartment, where the concentration is tightly regulated between 3.5 and 5 mmol/L[5][6]. This parameter is crucial for maintaining the resting membrane potential of excitable tissues like nerve and muscle and for ensuring proper function of cellular processes such as action potential generation, muscle contraction, and acid-base balance[2][5][7]. Potassium concentration is dynamically controlled by the sodium-potassium ATPase, renal excretion, hormonal influences (insulin, aldosterone), and acid-base status[5][7]. Disturbances in extracellular potassium can have serious physiological consequences, notably affecting cardiac and neuromuscular function[5]. Changes in this concentration are not properties of a molecular target, but represent a key measurable variable in physiology and medicine rather than a discrete drug target or molecular entity[5][6][7].

Other names

extracellular potassium concentrationextracellular K+plasma potassium

Drugs affect potassium excretion or reabsorption (diuretics increase excretion; potassium-sparing diuretics decrease excretion) Insulin promotes cellular uptake of potassium by stimulating Na^+/K^+-ATPase ACE inhibitors and ARBs decrease aldosterone, reducing potassium excretion