Thyroid hormone action: induction of morphological changes and protein secretion in astroglial cell cultures.
The effects of triiodothyronine (T3) on cell morphology and protein secretion were examined in astrocytes cultured in a chemically defined medium devoid of other hormones and growth factors. The flat polygonal astrocytic cells treated with T3 (1-50 nM) and maintained in non-renewed medium cultures were progressively transformed into process-bearing cells. These changes were initially observed 3 days after the end of T3 treatment and accounted for more than 50% of the cells 7-8 days thereafter. The proteins secreted by the T3-stimulated cells were analyzed on SDS-PAGE after cell labeling for 4.5 h with [35S]methionine. The effect of T3 on protein secretion was dose-dependent. Half-maximal stimulation was reached with 0.2-0.5 nM hormone and the proteins of 46, 59, 67, 78, 85 and 140 kDa were over-secreted (greater than 300% of control). These results were only obtained when the cell medium was not renewed after T3 treatment.
Gavaret
J M
JM
U. 96 INSERM, Unité de Recherche sur la Glande Thyroïde et Régulation Hormonale, Le Kremlin-Bicêtre, France.
Toru-Delbauffe
D
D
Baghdassarian-Chalaye
D
D
Pomerance
M
M
Pierre
M
M
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D008858:Microscopy, Phase-Contrast; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014284:Triiodothyronine / Q000502:physiology*
D009419:Nerve Tissue Proteins; D014284:Triiodothyronine