Linked Life Data

8967496

Source:http://linkedlifedata.com/resource/pubmed/id/8967496

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5 Pt 1
pubmed:dateCreated
1996-12-6
pubmed:abstractText
The question of sugar transport heterogeneity in the human intestinal Caco-2 cell line was addressed using alpha-methyl-D-glucose (AMG) and 2-deoxy-D-glucose (DG) as substrate analogues for D-glucose, the transport inhibitors phlorizin (PZ) and phloretin (PT), and NaCl or choline chloride uptake media. The data are compatible with the existence of three distinct pathways that can be isolated kinetically according to specific characteristics: 1) an "AMG-strict" system, strictly Na+ dependent and specific for AMG [Michaelis-Menten constant value (K(m)) = 2.0 +/- 0.3 mM] but sensitive to both PZ and PT, with PZ being more potent than PT, 2) a "DG-strict" system, strictly Na+ independent and specific for both DG (K(m) = 5.2 +/- 0.5 mM) and PT; and 3) a "DG/AMG-mixed" system, strictly Na+ dependent, with loose specificities for the glucose analogues DG (K(m) = 0.81 +/- 0.07 mM) and AMG (K(m) = 8.1 +/- 0.8 mM), and the inhibitors PZ and PT, but with PT being more potent than PZ. Since SGLT-1 obtained by polymerase chain reaction from either Caco-2 cells or normal human jejunum demonstrated identical transport properties when expressed in Xenopus laevis oocytes, we conclude that the "AMG-strict" system represents the expression of human SGLT-1 activity in this cell line. Moreover, Western blot analysis revealed that SGLT-1 is located exclusively in the apical membrane. In contrast, neither the nature nor the membrane location of both the DG-strict and DG/AMG-mixed pathways could be resolved unambiguously. Still it has been demonstrated that expression of the latter system is constitutive to all Caco-2 cells and that its Na+ dependence is not the consequence of H(+)-dependent transport activity. Aside from the presence of the DG/AMG-mixed system, a salient feature of Caco-2 cells is that the GLUT-3 protein is located exclusively in the brush-border membrane. Due to these limitations, it is concluded that the Caco-2 cell line cannot be considered as equivalent to either fetal colonic cells or normal enterocytes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Carbohydrates, http://linkedlifedata.com/resource/pubmed/chemical/Deoxyglucose, http://linkedlifedata.com/resource/pubmed/chemical/Glucose Transporter Type 3, http://linkedlifedata.com/resource/pubmed/chemical/Membrane Glycoproteins, http://linkedlifedata.com/resource/pubmed/chemical/Methylglucosides, http://linkedlifedata.com/resource/pubmed/chemical/Monosaccharide Transport Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Nerve Tissue Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Protons, http://linkedlifedata.com/resource/pubmed/chemical/SLC2A3 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/SLC5A1 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Sodium, http://linkedlifedata.com/resource/pubmed/chemical/Sodium-Glucose Transporter 1, http://linkedlifedata.com/resource/pubmed/chemical/methylglucoside
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
G833-43
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Kinetic separation and characterization of three sugar transport modes in Caco-2 cells.
pubmed:affiliation
Department of Physiology, Faculty of Medicine, University of Montreal, Quebec, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't