How does CKD affect kidney and colonic potassium excretion?
The loss of nephron mass in patients with progressive chronic kidney disease (CKD) is counterbalanced by an adaptive increase in potassium secretion by the functioning nephrons. This adaptation results in preserved potassium homeostasis until the glomerular filtration rate falls below 15 to 20 mL/min when hyperkalemia may ensue due to the inability to excrete daily dietary potassium load. In addition to kidney clearance, colonic potassium secretion is upregulated in advanced CKD as BK channels in the colonic mucosa increase several fold under the influence of aldosterone.
