K+ channels in the basolateral membrane of rat cortical collecting duct

The cortical collecting duct of the mammalian kidney is the most important nephron segment for the fine regulation of electrolyte excretion in the urine. The majority of the cells in this tubular segment, the principal cells, are responsible for Na+ reabsorption and K+ secretion. K+ secretion is functionally coupled to H+ secretion, which is the major task of the α-type intercalated cells in the cortical collecting duct. K+ secretion is decreased when H+ secretion is increased during acidosis [1–4]. Thus, disturbances in plasma K+ levels as well as in the acid base balance of the organism induce regulatory adjustments of transport in the distal nephron, mainly the collecting duct