Thyroid hormone transport in a human glioma cell line

Alfredo Pontecorvi, E. Goncalves, M. Lakshmanan, J. Robbins

Risultato della ricerca: Contributo in rivistaArticolo in rivista

16 Citazioni (Scopus)

Abstract

The uptake of 3,5,3'-triiodothyronine (T3) and thyroxine (T4) was studied in human glioma cells (Hs 683) and compared with that in several other neural cell lines. At 25 degrees C or 37 degrees C, total cell uptake rose rapidly and reached equilibrium within 60 min. The glioma cells had the highest uptake: 47.6 fmol of L-T3 and 43.4 fmol of L-T4 per 10(6) cells at 37 degrees C. These were inhibited 77% and 72%, respectively, by excess unlabeled hormone. Uptake in the nuclei reached equilibrium between 90 and 120 min and was also highest in glioma cells: 1.46 fmol of L-T3 and 0.49 fmol of L-T4 per 10(6) cells. When expressed as percent of total cell uptake, however, glioma cells had the lowest values (3.1% for L-T3 and 1.1% for L-T4). Also in contrast to other cell lines, glioma cells transported L-T4 almost as effectively as L-T3. D-T3 and D-T4 total cell uptake was 86% and 96% lower than that of the respective L-isomers, and the nuclear uptake as a fraction of the cell uptake was similar. Kinetic analysis of the initial rate of cell uptake gave Vmax values for D-T3 and D-T4 that were 97% and 98% lower than for the L-isomers. Antimycin and monodansylcadaverine decreased the Vmax as well as the equilibrium cell and nuclear uptake of the L-isomers. The apparent nuclear affinity constant for L-T4 in intact cells was inhibited 90% in the presence of antimycin, whereas no effect was observed in isolated nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)
Lingua originaleEnglish
pagine (da-a)157-165
Numero di pagine9
RivistaMolecular and Cellular Endocrinology
Volume69
Stato di pubblicazionePubblicato - 1990

Keywords

  • Aminoisobutyric Acids
  • Antimycin A
  • Binding, Competitive
  • Biological Transport
  • Cadaverine
  • Cell Membrane
  • Cell Nucleus
  • Glioma
  • Humans
  • Kinetics
  • Medulloblastoma
  • Neuroblastoma
  • Ouabain
  • Temperature
  • Thyroxine
  • Triiodothyronine
  • Tumor Cells, Cultured

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