Acid-Base and Potassium Homeostasis

Acid-base balance and potassium disorders are often clinically linked. Importantly, acid-base disorders alter potassium transport. In general, acidosis causes decreased K+ secretion and increased reabsorption in the collecting duct. Alkalosis has the opposite effects, often leading to hypokalemia. Potassium disorders also influence acid-base homeostasis. Potassium depletion causes increased H+ secretion, ammoniagenesis and H-K-ATPase activity. Hyperkalemia decreases ammoniagenesis and NH4+ transport in the thick ascending limb. Some combined potassium and acid-base disorders involve indirect factors such as aldosterone, impaired renal function, volume depletion, and diarrhea. In summary, disorders of potassium and acid-base homeostasis are mechanistically linked and clinically important. (C) 2013 Elsevier Inc. All rights reserved.