Absence of evidence of translocation of GLUT2 to the apical membrane of enterocytes in everted intestinal sleeves

Jeffrey S. Scow, Corey W. Iqbal, Thomas W. Jones, Hisham G. Qandeel, Ye Zheng, Judith A. Duenes, Munenori Nagao, Srivats Madhavan, Michael G. Sarr

Research output: Contribution to journalArticle

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Abstract

Introduction: Traditional models of intestinal glucose absorption confine GLUT2 to the basolateral membrane. Evidence suggests that GLUT2 is translocated to the apical membrane when the enterocyte is exposed to high luminal glucose concentrations. Hypothesis: GLUT2 translocates to the apical membrane by a PKC signaling mechanism dependent on activity of SGLT1 and the cellular cytostructure. Methods: Transporter-mediated glucose uptake was studied in rat jejunum using everted sleeves under seven conditions: Control, SGLT1 inhibition (phlorizin), GLUT2 inhibition (phloretin), both SGLT1 and GLUT2 inhibition, PKC inhibition (calphostin C or chelerythrine), and disruption of cellular cytostructure (nocodazole). Each condition was tested in iso-osmotic solutions of 1, 20, or 50 mM glucose for 1 or 5 min incubations (n = 6 rats each). Results: Control rats exhibited a saturable pattern of uptake at both durations of incubation. Phlorizin (P ≤ 0.006 each) inhibited markedly and phloretin (P ≤ 0.01 each) inhibited partially glucose uptake in all concentrations and time. Phloretin and phlorizin together completely inhibited uptake (P = 0.004 each). Calphostin C, chelerythrine, and nocodazole had little effect on glucose uptake at either 1 or 5 min. Inhibition of SGLT1 led to near complete cessation of transporter-mediated glucose uptake, while GLUT2 inhibition led to partial inhibition, suggesting some constitutive expression of GLUT2 in the apical membrane. Disruption of PKC signaling or cytoskeletal integrity partially inhibited transporter-mediated glucose uptake only in 1 mM glucose, suggesting a non-specific effect. Conclusions: Under these conditions, it does not appear that GLUT2 is translocated to the apical membrane on the cellular cytostructure in response to PKC signaling.

Original languageEnglish (US)
Pages (from-to)56-61
Number of pages6
JournalJournal of Surgical Research
Volume167
Issue number1
DOIs
StatePublished - May 1 2011

Fingerprint

Enterocytes
Phloretin
Phlorhizin
Glucose
Membranes
Facilitative Glucose Transport Proteins
Nocodazole
Intestinal Absorption
Jejunum

Keywords

  • glucose uptake
  • GLUT2
  • hexose transport
  • intestinal absorption
  • protein kinase C
  • SGLT1

ASJC Scopus subject areas

  • Surgery

Cite this

Scow, J. S., Iqbal, C. W., Jones, T. W., Qandeel, H. G., Zheng, Y., Duenes, J. A., ... Sarr, M. G. (2011). Absence of evidence of translocation of GLUT2 to the apical membrane of enterocytes in everted intestinal sleeves. Journal of Surgical Research, 167(1), 56-61. https://doi.org/10.1016/j.jss.2010.04.026

Absence of evidence of translocation of GLUT2 to the apical membrane of enterocytes in everted intestinal sleeves. / Scow, Jeffrey S.; Iqbal, Corey W.; Jones, Thomas W.; Qandeel, Hisham G.; Zheng, Ye; Duenes, Judith A.; Nagao, Munenori; Madhavan, Srivats; Sarr, Michael G.

In: Journal of Surgical Research, Vol. 167, No. 1, 01.05.2011, p. 56-61.

Research output: Contribution to journalArticle

Scow, JS, Iqbal, CW, Jones, TW, Qandeel, HG, Zheng, Y, Duenes, JA, Nagao, M, Madhavan, S & Sarr, MG 2011, 'Absence of evidence of translocation of GLUT2 to the apical membrane of enterocytes in everted intestinal sleeves', Journal of Surgical Research, vol. 167, no. 1, pp. 56-61. https://doi.org/10.1016/j.jss.2010.04.026
Scow, Jeffrey S. ; Iqbal, Corey W. ; Jones, Thomas W. ; Qandeel, Hisham G. ; Zheng, Ye ; Duenes, Judith A. ; Nagao, Munenori ; Madhavan, Srivats ; Sarr, Michael G. / Absence of evidence of translocation of GLUT2 to the apical membrane of enterocytes in everted intestinal sleeves. In: Journal of Surgical Research. 2011 ; Vol. 167, No. 1. pp. 56-61.
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abstract = "Introduction: Traditional models of intestinal glucose absorption confine GLUT2 to the basolateral membrane. Evidence suggests that GLUT2 is translocated to the apical membrane when the enterocyte is exposed to high luminal glucose concentrations. Hypothesis: GLUT2 translocates to the apical membrane by a PKC signaling mechanism dependent on activity of SGLT1 and the cellular cytostructure. Methods: Transporter-mediated glucose uptake was studied in rat jejunum using everted sleeves under seven conditions: Control, SGLT1 inhibition (phlorizin), GLUT2 inhibition (phloretin), both SGLT1 and GLUT2 inhibition, PKC inhibition (calphostin C or chelerythrine), and disruption of cellular cytostructure (nocodazole). Each condition was tested in iso-osmotic solutions of 1, 20, or 50 mM glucose for 1 or 5 min incubations (n = 6 rats each). Results: Control rats exhibited a saturable pattern of uptake at both durations of incubation. Phlorizin (P ≤ 0.006 each) inhibited markedly and phloretin (P ≤ 0.01 each) inhibited partially glucose uptake in all concentrations and time. Phloretin and phlorizin together completely inhibited uptake (P = 0.004 each). Calphostin C, chelerythrine, and nocodazole had little effect on glucose uptake at either 1 or 5 min. Inhibition of SGLT1 led to near complete cessation of transporter-mediated glucose uptake, while GLUT2 inhibition led to partial inhibition, suggesting some constitutive expression of GLUT2 in the apical membrane. Disruption of PKC signaling or cytoskeletal integrity partially inhibited transporter-mediated glucose uptake only in 1 mM glucose, suggesting a non-specific effect. Conclusions: Under these conditions, it does not appear that GLUT2 is translocated to the apical membrane on the cellular cytostructure in response to PKC signaling.",
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T1 - Absence of evidence of translocation of GLUT2 to the apical membrane of enterocytes in everted intestinal sleeves

AU - Scow, Jeffrey S.

AU - Iqbal, Corey W.

AU - Jones, Thomas W.

AU - Qandeel, Hisham G.

AU - Zheng, Ye

AU - Duenes, Judith A.

AU - Nagao, Munenori

AU - Madhavan, Srivats

AU - Sarr, Michael G.

PY - 2011/5/1

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N2 - Introduction: Traditional models of intestinal glucose absorption confine GLUT2 to the basolateral membrane. Evidence suggests that GLUT2 is translocated to the apical membrane when the enterocyte is exposed to high luminal glucose concentrations. Hypothesis: GLUT2 translocates to the apical membrane by a PKC signaling mechanism dependent on activity of SGLT1 and the cellular cytostructure. Methods: Transporter-mediated glucose uptake was studied in rat jejunum using everted sleeves under seven conditions: Control, SGLT1 inhibition (phlorizin), GLUT2 inhibition (phloretin), both SGLT1 and GLUT2 inhibition, PKC inhibition (calphostin C or chelerythrine), and disruption of cellular cytostructure (nocodazole). Each condition was tested in iso-osmotic solutions of 1, 20, or 50 mM glucose for 1 or 5 min incubations (n = 6 rats each). Results: Control rats exhibited a saturable pattern of uptake at both durations of incubation. Phlorizin (P ≤ 0.006 each) inhibited markedly and phloretin (P ≤ 0.01 each) inhibited partially glucose uptake in all concentrations and time. Phloretin and phlorizin together completely inhibited uptake (P = 0.004 each). Calphostin C, chelerythrine, and nocodazole had little effect on glucose uptake at either 1 or 5 min. Inhibition of SGLT1 led to near complete cessation of transporter-mediated glucose uptake, while GLUT2 inhibition led to partial inhibition, suggesting some constitutive expression of GLUT2 in the apical membrane. Disruption of PKC signaling or cytoskeletal integrity partially inhibited transporter-mediated glucose uptake only in 1 mM glucose, suggesting a non-specific effect. Conclusions: Under these conditions, it does not appear that GLUT2 is translocated to the apical membrane on the cellular cytostructure in response to PKC signaling.

AB - Introduction: Traditional models of intestinal glucose absorption confine GLUT2 to the basolateral membrane. Evidence suggests that GLUT2 is translocated to the apical membrane when the enterocyte is exposed to high luminal glucose concentrations. Hypothesis: GLUT2 translocates to the apical membrane by a PKC signaling mechanism dependent on activity of SGLT1 and the cellular cytostructure. Methods: Transporter-mediated glucose uptake was studied in rat jejunum using everted sleeves under seven conditions: Control, SGLT1 inhibition (phlorizin), GLUT2 inhibition (phloretin), both SGLT1 and GLUT2 inhibition, PKC inhibition (calphostin C or chelerythrine), and disruption of cellular cytostructure (nocodazole). Each condition was tested in iso-osmotic solutions of 1, 20, or 50 mM glucose for 1 or 5 min incubations (n = 6 rats each). Results: Control rats exhibited a saturable pattern of uptake at both durations of incubation. Phlorizin (P ≤ 0.006 each) inhibited markedly and phloretin (P ≤ 0.01 each) inhibited partially glucose uptake in all concentrations and time. Phloretin and phlorizin together completely inhibited uptake (P = 0.004 each). Calphostin C, chelerythrine, and nocodazole had little effect on glucose uptake at either 1 or 5 min. Inhibition of SGLT1 led to near complete cessation of transporter-mediated glucose uptake, while GLUT2 inhibition led to partial inhibition, suggesting some constitutive expression of GLUT2 in the apical membrane. Disruption of PKC signaling or cytoskeletal integrity partially inhibited transporter-mediated glucose uptake only in 1 mM glucose, suggesting a non-specific effect. Conclusions: Under these conditions, it does not appear that GLUT2 is translocated to the apical membrane on the cellular cytostructure in response to PKC signaling.

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KW - GLUT2

KW - hexose transport

KW - intestinal absorption

KW - protein kinase C

KW - SGLT1

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