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: Role of the electrochemical gradient for Na+ in D-glucose transport by mullet kidney.
    Author: Lee SH, Pritchard JB.
    Journal: Am J Physiol; 1983 Mar; 244(3):F278-88. PubMed ID: 6299114.
    Abstract:
    Brush border membrane vesicles were prepared from striped mullet (Mugil cephalus) kidney. As judged by the marker enzyme activities, these membranes were enriched 10- to 15-fold compared with the initial homogenate. Uptake of D-glucose was phlorizin sensitive and Na+ dependent. L-glucose uptake was unaffected by either phlorizin or Na+. D-Glucose uptake reflected entry into the osmotically active intravesicular space, not binding to the membranes. When Na+ was increased from 25 to 100 mM, the maximum velocity of glucose uptake was increased from 92 to 423 pmol . s-1 . mg protein-1, whereas the apparent Km (1.27 +/- 0.23) was not altered as Na+ increased. 22Na+ uptake by these membrane vesicles was stimulated by D-glucose and inhibited by phlorizin. These results indicated that Na+ and glucose entered the vesicles via a cotransport process. Consistent with this interpretation, it was possible to show that glucose uptake could be driven by either the chemical or electrical component of the Na+ electrochemical gradient and that the contributions of these two components were additive when both were present. Finally, it was shown that the coupling ratio between Na+ and glucose was approximately 1:1. Accordingly, these results indicate that reabsorption of D-glucose across the brush border membranes is coupled to the transmembrane electrochemical gradient of sodium ions.
    [Abstract] [Full Text] [Related] [New Search]