ISSN:
1432-2013
Keywords:
Kidney
;
Tubular Sodium Transport
;
Sodium Pump
;
Ion Transport
;
Perfusion of Kidney
;
Niere
;
Tubulärer Natrium-Transport
;
Natriumpumpe
;
Ionentransport
;
Nierenperfusion
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Transtubular absorption of Na and Cl, and intracellular ion concentrations were evaluated in toad kidneys perfused with solutions containing K and without K, and in the presence of 1 mM Ouabain and 1 mM Ethacrynic acid. The following values were obtained with 8.5 mM K: Transtubular absorption of Na and Cl∼68% (percent of filtered load); cell content 294 μmole Na, 433 μmole K, 100 μmole Cl/g solids. Lack of K in the perfusate diminished transtubular absorption to ∼25% and the cells gain 244 μmole Na/g solids, and lose an equimolecular quantity of K. The process is reversible upon raising the K concentration in the perfusate. Ouabain inhibits transtubular absorption to ∼6%; the cells lose about 110 μmole K/g solids, but cellular Na is maintained at the control levels. Ethacrynic acid inhibits transtubular absorption to ∼3%; the cells approximately double their Na and Cl content, but their K is maintained at the control levels. These observations cannot be explained exclusively in terms of an effect on the distal tubule. Probably proximal as well as distal tubules are involved. A single Na pump seems insufficient to account for all experimental findings. The existence of two separate pumps is therefore proposed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00592080
Permalink
