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Cell and Tissue Research

, Volume 285, Issue 1, pp 83–89 | Cite as

Immunolocalization of GLUT1 and connexin 26 in the rat placenta

  • Bo-Chul Shin
  • Takeshi Suzuki
  • Toshiyuki Matsuzaki
  • Shigeyasu Tanaka
  • Akio Kuraoka
  • Yosaburo Shibata
  • Kuniaki Takata

Abstract.

Interhemal membrane in the rat placenta is composed of three trophoblastic layers and endothelial cells. GLUT1, an isoform of the facilitated-diffusion glucose transporter, is abundant in the cells of the placental barrier, i.e., syncytiotrophoblastic layers I and II. GLUT1 is localized at the plasma membranes of the maternal-blood side of syncytiotrophoblastic layer I, and of the fetal-blood side of syncytiotrophoblastic layer II. Double-immunofluorescence microscopy has shown that connexin 26 is present between these GLUT1-positive sites, i.e., between syncytiotrophoblastic layers I and II. Immunogold electron microscopy has revealed that connexin 26 is localized in the gap junctions connecting the two layers. Connexin 26 in these layers therefore makes them functionally a single syncytial layer for the transfer of small molecules such as glucose in the rat placental barrier. These results suggest that glucose transfer in the rat placental barrier is carried out as follows: GLUT1 is used for the entry of glucose into the cytoplasm of syncytiotrophoblastic layer I, connexin 26 for the transfer of glucose from syncytiotrophoblastic layer I to syncytiotrophoblastic layer II, and GLUT1 for the exit of glucose to the fetal circulation.

Key words: Glucose transporter GLUT1 Connexin 26 Gap junctions Placenta Syncytiotrophoblast Rat (Wistar) 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Bo-Chul Shin
    • 1
  • Takeshi Suzuki
    • 1
  • Toshiyuki Matsuzaki
    • 1
  • Shigeyasu Tanaka
    • 1
  • Akio Kuraoka
    • 2
  • Yosaburo Shibata
    • 2
  • Kuniaki Takata
    • 1
  1. 1.Laboratory of Molecular and Cellular Morphology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma 371, JapanJP
  2. 2.Department of Anatomy, Faculty of Medicine, Kyushu University, Fukuoka 812, JapanJP

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