Pflügers Archiv

, Volume 429, Issue 3, pp 394–399 | Cite as

Immunolocalisation of nucleoside transporters in human placental trophoblast and endothelial cells: evidence for multiple transporter isoforms

  • L. F. Barros
  • D. L. Yudilevich
  • S. M. Jarvis
  • N. Beaumont
  • J. D. Young
  • S. A. Baldwin
Original Article Molecular and Cellular Physiology

Abstract

Polyclonal antibodies raised against the human erythrocyte nucleoside transporter were used to investigate the distribution of the nucleoside transporters in the placenta. Immunoblots of brush-border membranes isolated from the human syncytiotrophoblast revealed a cross-reactive species that co-migrated with the erythrocyte nucleoside transporter as a broad band of apparent Mr 55,000. In contrast, no labelling was detected in basal membranes containing a similar number of equilibrative nucleoside transporters as assessed by nitrobenzylthioinosine (NBMPR)-binding. The absence of cross-reactive epitopes in basal membranes and their presence in brush-border membranes was confirmed by confocal immunofluorescence microscopy. These results suggest that at least two isoforms of the NBMPR-sensitive nucleoside transporter are present in the human placenta. The lumenal surfaces of fetal capillaries, small placental vessels and umbilical vein were also strongly labelled by the antibody, a finding that suggests that the high fetal-placental adenosine uptake previously reported is due to endothelial transporters.

Key words

Nucleoside transport Nitrobenzylthioinosine (NBMPR) Microvillous and basal membrane vesicles Placenta (human) 

Abbreviations

NT

The human erythrocyte nucleoside transporter

Anti-NT

Polyclonal antibody against the nucleoside transporter

NBMPR

Nitrobenzylthioinosine {6-[(4-nitrobenzyl)thio]-9-β-D-ribofuranosylpurine}.

GLUTl

The human erythrocyte glucose transporter

PBS

Phosphate-buffered saline

TBS

TRIS-buffered saline

TTBS

TRIS-buffered saline containing 0.2% Tween-20

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Copyright information

© Springer Verlag 1995

Authors and Affiliations

  • L. F. Barros
    • 1
    • 2
  • D. L. Yudilevich
    • 1
  • S. M. Jarvis
    • 3
  • N. Beaumont
    • 2
  • J. D. Young
    • 4
  • S. A. Baldwin
    • 2
  1. 1.Departmento of Fisiología y BiofísicaUniversidad de ChileSantiago 7Chile
  2. 2.Department of Biochemistry and Molecular BiologyUniversity of LeedsLeedsUK
  3. 3.Research School of BiosciencesUniversity of KentCanterburyUK
  4. 4.Department of PhysiologyUniversity of AlbertaEdmontonCanada

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