scholarly journals Regulation of active sodium and potassium transport in the distal colon of the rat. Role of the aldosterone and glucocorticoid receptors.

1989 ◽  
Vol 84 (6) ◽  
pp. 1924-1929 ◽  
Author(s):  
S G Turnamian ◽  
H J Binder
Keyword(s):  
Glucocorticoid Receptors ◽  
Distal Colon ◽  
Potassium Transport ◽  
Active Sodium ◽  
Sodium And Potassium

scholarly journals Sodium and Potassium Uptake by Seedlings of Hordeum Vulgare

1965 ◽  
Vol 18 (1) ◽  
pp. 10 ◽  
Author(s):  
MG Pitman
Keyword(s):  
Hordeum Vulgare ◽  
Water Flow ◽  
Divalent Cations ◽  
Potassium Transport ◽  
Potassium Uptake ◽  
Active Process ◽  
Experimental Conditions ◽  
Sodium Uptake ◽  
Sodium And Potassium

Uptake of potassium and sodium from culture solutions by barley seedlings under a range of experimental conditions has been determined. It was shown that both sodium and potassium transport to the shoot was due to an active process in the root which was limited by the plant's growth. This process was not available for uptake of divalent cations. Sodium uptake at higher concentrations showed some relation to transpiration and the resulting increase in sodium uptake with concentration reduced the selectivity in the plant for potassium to sodium. It was shown that potassium transport across the root was independent of water flow to the cytoplasm. The role of the cytoplasm in selective ion uptake to the shoot is discussed.

Renal Na-K-ATPase: its role in tubular sodium and potassium transport

1982 ◽  
Vol 242 (3) ◽  
pp. F207-F219 ◽  
Author(s):  
A. I. Katz
Keyword(s):  
Cation Transport ◽  
Potassium Transport ◽  
Secondary Active Transport ◽  
Nephron Segments ◽  
Single Nephron ◽  
Acute Changes ◽  
K Transport ◽  
Sodium And Potassium ◽  
Slow Turnover

Na-K-ATPase, the enzymatic equivalent of the sodium:potassium pump, is found in large amounts in the kidney, and this organ has figured prominently both as a source for the purification of the enzyme and as a target for the study of its properties. Located on the basolateral aspect of tubule cells, renal Na-K-ATPase plays a key role in the active translocation of Na and K across this membrane as well as in the "secondary active" transport of a number of other solutes. The activity of renal Na-K-ATPase varies in parallel with sustained changes in Na or K transport, indicating the participation of this enzyme in the chronic adaptation of the kidney to altered Na reabsorption or K secretory load. Because of its slow turnover, however, the role of Na-K-ATPase in the modulation of acute changes in cation transport is unclear. Several hormones and vanadate influence renal Na-K-ATPase activity, and their importance as potential physiologic regulators of this enzyme is examined. Most of the information on the renal enzyme has been obtained from studies using homogenates or subcellular fractions thereof, but more recently the development of tubule microdissection and microanalytic methods has made possible the study of Na-K-ATPase in single nephron segments. This approach has opened new possibilities for evaluating the role of this enzyme in kidney function by facilitating correlation of enzyme activity with transport events in the same structure and by enabling us to focus the study of Na-K-ATPase on discrete anatomic subdivisions of the functionally heterogeneous nephron.

Sodium and potassium handling by the aldosterone-sensitive distal nephron: the pivotal role of the distal and connecting tubule

2004 ◽  
Vol 287 (4) ◽  
pp. F593-F601 ◽  
Author(s):  
Pierre Meneton ◽  
Johannes Loffing ◽  
David G. Warnock
Keyword(s):  
Sodium Intake ◽  
Collecting Duct ◽  
Genetic Defect ◽  
Potassium Transport ◽  
The Body ◽  
Dietary Sodium ◽  
Sodium Reabsorption ◽  
Connecting Tubule ◽  
Sodium And Potassium

Sodium reabsorption and potassium secretion in the distal convoluted tubule and in the connecting tubule can maintain the homeostasis of the body, especially when dietary sodium intake is high and potassium intake is low. Under these conditions, a large proportion of the aldosterone-regulated sodium and potassium transport would occur in these nephron segments before the tubular fluid reaches the collecting duct. The differences between these two segments and the collecting duct would be more quantitative than qualitative. The collecting duct would come into play when the upstream segments are overloaded by a primary genetic defect that affects sodium and/or potassium transport or by a diet that is exceedingly poor in sodium and rich in potassium. It is likely that the homeostatic role of the distal convoluted and connecting tubules, which are technically difficult to study, has been underestimated, whereas the role of the more easily accessible collecting duct may have been overemphasized.

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