Acid-Base and Potassium Homeostasis☆
Section snippets
Overall Potassium Homeostasis
Acid-base balance is one of the important factors that affect potassium regulation. As such, an overview of potassium homeostasis is necessary to put the influence of acid-base disorders on potassium in context. Although the kidneys are responsible for day-to-day potassium balance, the first level of control of plasma potassium involves the relationship with total body and intracellular potassium. Importantly, some of the most common abnormalities in potassium occur in the setting of acute
Renal Potassium Handling
Maintaining normal potassium balance is dependent on three basic processes: (1) K+ intake; (2) K+ excretion; and (3) internal distribution of K+ between the extracellular and intracellular fluid compartments. Dietary K+ intake (usually 80-120 mmol/d) must be excreted to remain in balance. With the limited excretion of K+ by the colon (~5% to 10% of ingested K+), the kidneys are largely responsible for excreting the majority of ingested K+ (about 90%-95% of daily K+ intake).
Of note, dietary K+
Regulation of Renal Potassium Transport
The major variable component of renal K+ transport is K+ secretion and is the target of most regulatory factors. These factors are summarized in Table 1. As noted, aldosterone and distal nephron sodium reabsorption are major regulators of K+ secretion. One of the most potent factors that stimulates K+ secretion is the luminal flow rate.24, 25 Under all conditions, an increased luminal flow rate (including increased urine flow during volume expansion, osmotic diuresis, or use of diuretics)
Effects of acid-base ABNORMALITIES ON Renal Potassium Transport
Acid-base abnormalities alter potassium transport by several well-known mechanisms that are discussed. Potassium abnormalities also affect acid-base homeostasis, which is discussed in a subsequent section (Table 2 and Figure 1). Also, clearly a number of conditions (such as disorders of aldosterone) affect both potassium and acid-base homeostasis.
Acidosis, in addition to causing redistribution of potassium between cells and extracellular fluid, causes both decreased potassium secretion and
Hyperkalemia in Acidosis
In many conditions of acidosis, there is accompanying hyperkalemia (Table 3). In cases of acute metabolic acidosis, acute hyperkalemia frequently occurs from a number of different mechanisms such as impaired cellular potassium uptake from effects on Na,K-ATPase, decreased urinary excretion of potassium or tissue necrosis which directly leads to potassium cellular efflux. As noted earlier, so-called mineral acidosis or hyperchloremic acidosis directly can shift K+ out of cells into the
References (66)
- et al.
Changes in plasma potassium concentration during acute acid-base disturbances
Am J Med
(1981) - et al.
Potassium transport: from clearance to channels and pumps
Kidney Int
(1996) - et al.
Role of the kidney in potassium homeostasis: lessons from acid-base disturbances
Kidney Int
(1975) - et al.
Modulation of the secretion of potassium by accompanying anions in humans
Kidney Int
(1991) - et al.
Colonic H+-K+-ATPase is induced and mediates increased HCO3- reabsorption in inner medullary collecting duct in potassium depletion
Kidney Int
(1998) - et al.
Systemic and renal acid-base effects of chronic dietary potassium depletion in humans
Kidney Int
(1982) - et al.
Renal ammoniagenesis in humans with chronic potassium depletion
Kidney Int
(1991) - et al.
NH4+ secretion in inner medullary collecting duct in potassium deprivation: role of colonic H+-K+-ATPase
Kidney Int
(1999) - et al.
Dietary NaCl determines severity of potassium depletion-induced metabolic alkalosis
Kidney Int
(1987) - et al.
Renin-aldosterone system can respond to furosemide in patients with hyperkalemic hyporeninism
J Lab Clin Med
(1998)
On the pathogenesis of metabolic alkalosis in hyperaldosteronism
Am J Med
Relationship between blood pH and potassium and phosphorus during acute metabolic acidosis
Am J Physiol
Serum potassium in lactic acidosis and ketoacidosis
N Engl J Med
Serum potassium concentration in acidemic states
Nephron
Acute metabolic acidosis: characterization and diagnosis of the disorder and the plasma potassium response
J Am Soc Nephrol
Effects of pH on potassium: new explanations for old observations
J Am Soc Nephrol
Renal potassium transport: mechanisms and regulation
Am J Physiol
Effect of barium on potassium diffusion across the proximal convoluted tubule of the anesthetized rat
Am J Physiol
Estimated potassium reflection coefficient in perfused proximal convoluted tubules of the anaesthetized rat in vivo
J Physiol
Potassium channels along the nephron
Fed Proc
Stretch- and volume-activated channels in isolated proximal tubule cells
Am J Physiol
Potassium channels in Necturus proximal tubule
Am J Physiol
Ion transport mechanisms in thick ascending limb of Henle's loop of mammalian nephron
Physiol Rev
Control of NaCl transport in the thick ascending limb
Am J Physiol
Localization of ROMK channels in the rat kidney
J Am Soc Nephrol
Renal and extrarenal sites of action of diuretics
Cardiovasc Drugs Ther
Active potassium absorption by the renal distal tubule
Am J Physiol
Renal potassium transport: contributions of individual nephron segments and populations
Am J Physiol
Structural aspects of adaptive changes in renal electrolyte excretion
Am J Physiol
Structural-functional relationship along the distal nephron
Am J Physiol
Micropuncture study of renal potassium excretion in the rat
Am J Physiol
Role of NKCC in BK channel-mediated net K+ secretion in the CCD
Am J Physiol Renal Physiol
Effects of flow rate and potassium intake on distal tubular potassium transfer
Am J Physiol
Cited by (61)
Pyroglutamate acidosis 2023. A review of 100 cases
2024, Clinical Medicine, Journal of the Royal College of Physicians of LondonPotassium homeostasis – Physiology and pharmacology in a clinical context
2023, Pharmacology and TherapeuticsAge-related effect of high-frequency LED lighting in laying hens on biochemical, enzymatical, and electrolytes variables
2023, Journal of Applied Poultry ResearchNephrotoxicity of marketed antisense oligonucleotide drugs
2022, Current Opinion in ToxicologyAge-related effects of feeder space availability on welfare of broilers reared to 56 days of age part 1: biochemical, enzymatical, and electrolyte variables
2022, Journal of Applied Poultry ResearchDispelling myths and misconceptions about the treatment of acute hyperkalemia
2022, American Journal of Emergency Medicine
- ☆
Financial disclosure and conflict of interest statements: none.