Abstract
From previous studies, it is known that in the diluting segment, Cl--ions are transported from the tubule lumen into the cell together with Na+ and K+ via a furosemide-sensitive cotransport system. This carrier-mediated process, located in the luminal cell membrane, is driven by the steep "downhill" Na+ gradient (directed from lumen to cell) which is maintained by the ouabain-sensitive Na+/K+-pump at the peritubular cell membrane. Cl--ions are accumulated within the cell cytosol and are supposed to leave the cell by a Cl--conductive pathway. The present experiments, performed in diluting segments of the isolated perfused frog kidney, demonstrate the existence of a significant Cl--permeability of the peritubular cell membrane and its complete inhibition by anthracene-9-COOH. The data indicate that Cl--reabsorption can be reduced not only by the inhibition of luminal Cl--entry (i.e. by furosemide) but also by the blockade of the passive Cl--exit step across the peritubular cell membrane. Since complete inhibition of Cl--permeability reduces transepithelial uphill Cl--transport only to half, the data disclose the existance of an additional Cl--pathway at the peritubular cell membrane.
Original language | English (US) |
---|---|
Pages (from-to) | 172-174 |
Number of pages | 3 |
Journal | Pflügers Archiv European Journal of Physiology |
Volume | 398 |
Issue number | 2 |
DOIs | |
State | Published - Jul 1 1983 |
Keywords
- Amphibian kidney
- Anthracene-9-COOH
- Chloride permeability
- Diluting segment
ASJC Scopus subject areas
- Physiology
- Clinical Biochemistry
- Physiology (medical)