The transport properties of potassium (K) and sodium (Na) were studied in single distal tubules of Amphiuma using free-flow micropuncture techniques and stationary microperfusion methods. The transepithelial movement of labeled potassium was measured utilizing a three-compartment system in series in which the time course of tracer disappearance from the lumen was followed. Under control conditions, in blood- and doubly-perfused kidneys, extensive active net reabsorption of sodium and potassium obtains along single distal tubules. Tubular potassium reabsorption is abolished by ouabain at a concentration of 5 x 10-6 M. Significant net secretion of K can be induced by exposing Amphiuma to a high K environment (100 mM KCl) or by adding acetazoleamide (1 x 10-4 M) to the perfusion fluid. Transepithelial movement of potassium involves mixing with only a small fraction of total distal tubular cell potassium. This transport pool of potassium increases significantly with the transition from tubular net reabsorption to net secretion. Indirect evidence is presented which indicates that increased active K uptake across the peritubular cell boundary may be of prime importance during states of net K secretion.
Article|
May 01 1971
Potassium and Sodium Transport across Single Distal Tubules of Amphiuma
M. Wiederholt,
M. Wiederholt
From the Departments of Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, Cornell University Medical College, New York 10021, and New York University School of Medicine, New York 10016.
Search for other works by this author on:
W. J. Sullivan,
W. J. Sullivan
From the Departments of Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, Cornell University Medical College, New York 10021, and New York University School of Medicine, New York 10016.
Search for other works by this author on:
G. Giebisch
G. Giebisch
From the Departments of Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, Cornell University Medical College, New York 10021, and New York University School of Medicine, New York 10016.
Search for other works by this author on:
M. Wiederholt
From the Departments of Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, Cornell University Medical College, New York 10021, and New York University School of Medicine, New York 10016.
W. J. Sullivan
From the Departments of Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, Cornell University Medical College, New York 10021, and New York University School of Medicine, New York 10016.
G. Giebisch
From the Departments of Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, Cornell University Medical College, New York 10021, and New York University School of Medicine, New York 10016.
Dr. Wiederholt's present address is Institut für Klinische Physiologie, Klinikum Steglitz der Freien Universität Berlin, 1 Berlin 45, Germany. Dr. Sullivan's present address is Department of Physiology, New York University School of Medicine, New York 10016. Dr. Giebisch's present address is Department of Physiology, Yale University School of Medicine, New Haven, Connecticut 06510.
Received:
August 03 1970
Online Issn: 1540-7748
Print Issn: 0022-1295
Copyright © 1971 by The Rockefeller University Press
1971
J Gen Physiol (1971) 57 (5): 495–525.
Article history
Received:
August 03 1970
Citation
M. Wiederholt, W. J. Sullivan, G. Giebisch; Potassium and Sodium Transport across Single Distal Tubules of Amphiuma . J Gen Physiol 1 May 1971; 57 (5): 495–525. doi: https://doi.org/10.1085/jgp.57.5.495
Download citation file: