All regulation of renal potassium excretion & total body potassium balance occurs in: (A) Proximal convoluted tubule, (B) Ascending loop of Henle, (C) Descending loop of Henle, (D) Collecting duct
Answer is D. Changes in whole-body K+ content are primarily mediated by the kidney, which reabsorbs filtered K+ in hypokalemic, K+-deficient states and secretes K+ in hyperkalemic, K+-replete states. Although K+ is transpoed along the entire nephron, it is the principal cells of the connecting segment (CNT) and coical CD that play a dominant role in renal K+ secretion, whereas alpha-intercalated cells of the outer medullary CD function in renal tubular reabsorption of filtered K+ in K+-deficient states. Ref: Harrison 19e pg: 304