These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Vanadyl ions stimulate K+ uptake into isolated perfused rat liver via the Na+/K+-pump by a tyrosine kinase-dependent mechanism.
    Author: Bruck R, Halpern Z, Aeed H, Shechter Y, Karlish SJ.
    Journal: Pflugers Arch; 1998 Apr; 435(5):610-6. PubMed ID: 9479013.
    Abstract:
    Vanadium salts mimic most metabolic effects of insulin in vitro. We report here that vanadyl sulfate (VOSO4) and sodium vanadate (NaVO3) stimulate net K+ uptake in isolated perfused rat liver. Stimulation was evident at low concentrations of vanadyl ions (range 1-20 microM) and occurred within minutes following the addition of VOSO4. By comparison with VOSO4, insulin had less of a stimulatory effect on K+ uptake. Ouabain prevented the activating effect of VOSO4 on K+ uptake. Following a VOSO4 challenge, measured intracellular Na+ concentration ([Na+]i) fell (control, 17.1 +/- 1.2; VOSO4-treated, 13.0 +/- 1.1 mmol.g-1 wet weight, P = 0.027). The results indicate that active K+ uptake via the Na+/K+-ATPase was stimulated by vanadyl ions. An indirect mechanism due to changes in [Na+]i can be excluded. The tyrosine kinase inhibitor genistein was found to inhibit stimulation of K+ by vanadyl and vanadate ions which are known inhibitors of phosphotyrosine phosphatases. We conclude that stimulation of active K+ influx involves a tyrosine kinase. Possible mechanisms include phosphorylation at tyrosine residues and direct activation of the Na+/K+-ATPase, or phosphorylation of other proteins that regulate the activity or number of pumps in the cells.
    [Abstract] [Full Text] [Related] [New Search]