Dissociation of Na-K-ATPase specific activity and net reabsorption of sodium
Abstract:
Prevoius studies have suggested that the increase in specific activity of Na-K-ATPase in renal tissue during treatment with glucocorticoids occurred as a result of aconcurrent rise in net tubular reabsorption of sodium. Since recent data have indicated a specific effect of glucocortiocoids on epithelial cells, experiments were performed to determine whether enzyme activity and net sodium reabsorption could be dissociated. Evidence is provided demonstrating that base-line specific activity of Na-K-ATPase in rat renal cortex and outer medulla does not correlate directly with net sodium reabsorption since enzyme activity did not change after a chronic reduction in glomerularfiltration rate and the rate of sodium reabsorption. Further studies showed a markedrise in Na-K-ATPase after 4 days of treatment with methylprednisolone despite a fall in sodium absorption. These results suggest a direct effect of glucocorticoids onrenal Na-K-ATPase and illistrate the difficulty in assigning a transport role tothis enzyme from the correlation of specific activity with rates of net electrolyte transport.
More Related Videos
07:38Functional Characterization of Na+/H+ Exchangers of Intracellular Compartments Using Proton-killing Selection to Express Them at the Plasma Membrane
Published on: March 30, 2015
11:51Application of Electrophysiology Measurement to Study the Activity of Electro-Neutral Transporters
Published on: February 3, 2018
Related Concept Videos
Primary Active Transport
Primary Active Transport
ATP Driven Pumps III: V-type Pumps
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
Reabsorption and Secretion in the PCT
Transport mechanisms involving sodium ions (Na+) contribute significantly to solute reabsorption. These mechanisms include symport and antiport processes.
A key example is the...
Reabsorption and Secretion in the Loop of Henle
Active Transport
Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...
