Control of potassium excretion: a Paleolithic perspective

Curr Opin Nephrol Hypertens. 2006 Jul;15(4):430-6. doi: 10.1097/01.mnh.0000232884.73518.9c.

Abstract

Purpose of review: Regulation of potassium (K) excretion was examined in an experimental setting that reflects the dietary conditions for humans in Paleolithic times (high, episodic intake of K with organic anions; low intake of NaCl), because this is when major control mechanisms were likely to have developed.

Recent findings: The major control of K secretion in this setting is to regulate the number of luminal K channels in the cortical collecting duct. Following a KCl load, the K concentration in the medullary interstitial compartment rose; the likely source of this medullary K was its absorption by the H/K-ATPase in the inner medullary collecting duct. As a result of the higher medullary K concentration, the absorption of Na and Cl was inhibited in the loop of Henle, and this led to an increased distal delivery of a sufficient quantity of Na to raise K excretion markedly, while avoiding a large natriuresis. In addition, because K in the diet was accompanied by 'future' bicarbonate, a role for bicarbonate in the control of K secretion via 'selecting' whether aldosterone would be a NaCl-conserving or a kaliuretic hormone is discussed.

Summary: This way of examining the control of K excretion provides new insights into clinical disorders with an abnormal plasma K concentration secondary to altered K excretion, and also into the pathophysiology of calcium-containing kidney stones.

Publication types

  • Review

MeSH terms

  • Animals
  • Humans
  • Kidney Calculi / blood
  • Kidney Calculi / enzymology*
  • Kidney Calculi / urine
  • Kidney Tubules, Collecting / enzymology*
  • Kidney Tubules, Collecting / pathology
  • Loop of Henle / enzymology*
  • Loop of Henle / pathology
  • Natriuresis
  • Potassium / blood*
  • Potassium / urine
  • Rats
  • Sodium Chloride / blood
  • Sodium Chloride / urine
  • Sodium-Potassium-Exchanging ATPase / metabolism*
  • Water-Electrolyte Balance

Substances

  • Sodium Chloride
  • Sodium-Potassium-Exchanging ATPase
  • Potassium