Gut Sensing of Potassium Intake and its Role in Potassium Homeostasis

Abstract

Extracellular K+ homeostasis has been explained by feedback mechanisms in which changes in extracellular K+ concentration drive renal K+ excretion directly or indirectly via stimulating aldosterone secretion. However, this cannot explain meal-induced kaliuresis that often occurs without increases in plasma K+ or aldosterone concentration. Recent studies have produced evidence supporting a feedforward control in which gut sensing of dietary K+ increases renal K+ excretion (and extrarenal K+ uptake) independent of plasma K+ concentrations, namely, a “gut factor”. This review focuses on these new findings and discusses the role of gut factor in acute and chronic regulation of extracellular K+ as well as in the beneficial effects of high K+ intake on the cardiovascular system.

Regulation of Potassium Homeostasis

“…These studies suggest that dietary K 1 intake through a splanchnic sensing mechanism can signal increases in renal K 1 excretion independent of changes in plasma K 1 concentration or aldosterone (reviewed in ref. 80).…”

Electrolyte and acid‐base abnormalities associated with purging behaviors

“…The serum potassium level is normally maintained within a narrow range with little daily variation due to intricate renal and extrarenal mechanisms . Therefore, treatment of hypokalemia is critical for the health of the eating disorder patient, because of the widespread adverse clinical abnormalities that may follow in the wake of potassium depletion.…”

Potassium homeostasis, oxidative stress, and human disease

“…Through this mechanism the enteric sensors may enhance the clearance of the K + from diet or infusion 36–38 . A study has also suggested that dietary K + intake through a splanchnic sensing mechanism can signal increases in renal K + excretion independent of changes in plasma K + concentration or aldosterone 20 .…”

“…High blood pressure can be influenced by the levels of plasma potassium, low potassium causes hypertension and increasing potassium intake lowers blood pressure 20,107 . The blood pressure of people with hypertension is lowered when they are given K + supplements.…”

“…The colon is the major site of gut regulation of potassium excretion. Potassium excretion via the colon is minimal during normal conditions but its role increases as the renal function worsens as seen in renal insufficiency or during acute potassium overload when the kidneys are overwhelmed 12,20 .…”