Potassium homeostasis and renal potassium handling
Where the body keeps its potassium, what shifts it into and out of cells, how the distal nephron secretes it under aldosterone and flow, and how to use the urine potassium to creatinine ratio to separate renal from extrarenal losses.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Total body potassium is about 3,500 mmol, and 98% sits inside cells at about 140 mmol/L. The ECF holds only 60 to 70 mmol.
- A single meal can contain as much potassium as the whole ECF. Internal balance (shift into cells) buffers it within minutes. External balance (renal excretion) clears it over hours.
- The kidney filters about 700 mmol/day and reabsorbs almost all of it before the distal nephron. Urinary potassium is decided by secretion in the aldosterone-sensitive distal nephron.
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Sources
- Brenner and Rector's The Kidney (11th ed.)Elsevier (Yu, Chertow, Luyckx et al., 2020), 2020
- Guyton and Hall Textbook of Medical Physiology (14th ed.)Elsevier (Hall and Hall, 2021), 2021
- Palmer BF, Clegg DJ. Physiology and pathophysiology of potassium homeostasis. Adv Physiol Educ 2016;40(4):480-90American Physiological Society, 2016
- Kamel KS, Halperin ML. Intrarenal urea recycling leads to a higher rate of renal excretion of potassium: an hypothesis with clinical implications. Curr Opin Nephrol Hypertens 2011;20(5):547-54Current Opinion in Nephrology and Hypertension, 2011
- Chronic kidney disease (CKD) management in primary care (5th ed.)AU/NZKidney Health Australia, 2024
- Last updated
- 14 November 2026
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