Mechanism of enhanced transcellular potassium–secretion in man with chronic renal failure

Abstract

Previous studies from our laboratory demonstrated that net K secretion in human rectum was 2.5-fold higher in patients with chronic renal failure than in controls. The present study was performed to determine whether K secretion in human large intestine involves an active process and whether an active transport process accounts, at least in part, for the rise in net K secretion in patients with renal insufficiency. Studies were performed under conditions when net water and electrolyte transport approached zero, and the observed distribution of K and Na across the rectal mucosa was compared to expected equilibrium values. In control subjects an active transport of 27.6 +/- 2.6 mV was observed for K and 63 +/- 4.2 mV for Na. Similar values were demonstrated in patients with chronic renal failure. The results of these studies demonstrated that net secretion of K and absorption of Na are governed, at least in part, by active transport processes, and suggest that, since active K secretion is not impaired, the rise in net K secretion in patients with renal insufficiency is caused by active secretion as well as by passive driving forces.

Colonic potassium handling

“…In the context of this review the intestinal wasting of K + is common to most diarrhoeal diseases and often these present with extreme, acute hypokalemia [1]. Augmented intestinal K + excretion also becomes a relevant quantitative phenomenon in end-stage renal disease, where the colon is able to partially substitute for the reduced renal K + excretory capacity [4,57,76,87,104,105,115]. The current understanding of the mechanism and regulation of mammalian intestinal K + absorption and secretion is the major focus of this review.…”

A New Treatment forInterdialytic Hyperkalemia – The Use of Fosinopril Sodium

“…This preferential affinity may be the cause of less hyperkalemia through less aldosterone suppression than other ACEI. CRF patients have higher K excretion through the gut and sweat [13]. Panese et al [13] proved net K excretion in the rectum of CRF patients was 2.5 times higher than the control.…”

Potassium and anaesthesia

“…69 When uraemia develops, gastrointestinal secretion of potassium increases. 19,20,[205][206][207] When creatinine clearance is <20% normal, gastrointestinal potassium loss can approach 20% of intake. ~9 With progressive acidosis during uraemia, even mild extracellular shift forces can cause rapid hyperkalaemia.…”