Active potassium absorption by the renal distal tubule.

摘要: Maintenance of potassium homeostasis during depletion appears to involve an active absorptive mechanism in the distal nephron. Direct demonstration such a pathway tubule rat has been lacking. The purpose current study was examine hypothesis that ATP-dependent transport plays role absorption by tubule. We utilized vivo microperfusion techniques Sprague-Dawley rats maintained on regular diet low-potassium for 3-4 wk. effect selective inhibitor gastric H-K-adenosinetriphosphatase (ATPase) (Sch 28080, 0.1 mM) tested tubules both groups rats. Distal normal secreted potassium. Sch 28080 had no this net flux. In contrast, potassium-deficient absorbed abolished and produced small hyperpolarization lumen-negative transepithelial voltage (VTE). change VTE can be explained concomitant increase concentration late These results are consistent with presence H-K-ATPase