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: Modulation of myo-[3H]inositol uptake by glucose and sorbitol in cultured bovine lens epithelial cells. II. Characterization of high- and low-affinity myo-inositol transport sites.
    Author: Cammarata PR, Chen HQ, Yang J, Yorio T.
    Journal: Invest Ophthalmol Vis Sci; 1992 Dec; 33(13):3572-80. PubMed ID: 1464503.
    Abstract:
    Myo-[3H]inositol accumulation in cultured bovine lens epithelial cells (BLECs) occurred by high- and low-affinity, Na(+)-dependent transport sites. The high- and low-affinity transport systems had a Km of 27 +/- 4 and 157 +/- 22 mumol/l, respectively, and Vmax of 652 +/- 35 and 2952 +/- 308 pmol/mg protein/hr, respectively. The uptake of myo-[3H]inositol was lowered after chronic (20 hr) incubation of cultured cells in 40 mmol/l glucose throughout the concentration range for 1.5-400 mumol/l myo-inositol. The coadministration of sorbinil (0.1 mmol/l) to 40 mmol/l glucose partially prevented the inhibitory effect of glucose on myo-[3H]inositol uptake. Although the aldose reductase inhibitor prevented the inhibitory effect of glucose on the low-affinity transport site, a glucose-sensitive process for myo-[3H]inositol uptake on the high-affinity transport site was uncovered by Lineweaver-Burk analysis. Acute exposure (3 hr) of cultured BLECs maintained in physiologic medium (Eagle's minimal essential medium, 5.5 mmol/l glucose) to a range of 5.5-44 mmol/l glucose plus sorbinil also caused a decrease in myo-[3H]inositol uptake. Dixon plot analysis confirmed that the acute effect of glucose was the result of competitive inhibition of the high-affinity myo-inositol transport site. Acute exposure of cultured cells to 10-40 mmol/l sorbitol also diminished the accumulation of myo-[3H]inositol. Dixon plot analysis established that the acute effect of exogenous sorbitol was the result of competitive inhibition of the low-affinity myo-inositol transport site.(ABSTRACT TRUNCATED AT 250 WORDS)
    [Abstract] [Full Text] [Related] [New Search]