Glucose transport by acinar cells in rat parotid glands

Cell Physiol Biochem. 2012;29(3-4):325-30. doi: 10.1159/000338487. Epub 2012 Apr 3.

Abstract

Background/aims: Salivary glucose is often considered as being from glandular origin. Little information is available, however, on the possible role of glucose transporters in the secretion of the hexose by salivary glands. The major aim of the present study was to investigate the expression and localization of several distinct glucose transporters in acinar cells of rat parotid glands.

Methods: Quantitative real-time PCR analysis, immunohistochemistry and western blotting techniques were used to assess the presence of SGLT1, GLUT1, GLUT2 and GLUT4 in acinar cells of rat parotid glands.

Results: Quantitative real-time PCR documented the expression of SGLT1 and GLUT1 in parotid tissues, with a much lower level of GLUT4 mRNA and no expression of GLUT2 mRNA. Western blot analysis revealed the presence of SGLT1, GLUT1 and GLUT4 proteins, but not GLUT2 proteins in the parotid extract. Immunohistochemistry confirmed these findings. SGLT1 was specifically located at the baso-lateral membrane, co-localizing with Na(+)/K(+) ATPase. GLUT1 was found both at the baso-lateral and apical level. GLUT4 appeared to be also located at the baso-lateral level. However, too little GLUT4 was present to allow co-localization labeling.

Conclusion: Based on these findings, a model is proposed for the transport of glucose into the acinar cells and thereafter into the acinar lumen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinar Cells / cytology
  • Acinar Cells / metabolism*
  • Animals
  • Biological Transport
  • Cell Membrane / metabolism
  • Female
  • Gene Expression Regulation
  • Glucose / metabolism*
  • Glucose Transport Proteins, Facilitative / genetics
  • Glucose Transport Proteins, Facilitative / metabolism*
  • Glucose Transporter Type 1 / genetics
  • Glucose Transporter Type 1 / metabolism
  • Glucose Transporter Type 2 / genetics
  • Glucose Transporter Type 2 / metabolism
  • Immunohistochemistry
  • Kidney / cytology
  • Kidney / metabolism
  • Pancreas / cytology
  • Pancreas / metabolism
  • Parotid Gland / cytology
  • Parotid Gland / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sodium-Glucose Transporter 1 / genetics
  • Sodium-Glucose Transporter 1 / metabolism*
  • Sodium-Potassium-Exchanging ATPase / metabolism

Substances

  • Glucose Transport Proteins, Facilitative
  • Glucose Transporter Type 1
  • Glucose Transporter Type 2
  • RNA, Messenger
  • Slc2a1 protein, rat
  • Slc2a2 protein, rat
  • Slc5a1 protein, rat
  • Sodium-Glucose Transporter 1
  • Sodium-Potassium-Exchanging ATPase
  • Glucose