Thyroid hormone induces cerebellar astrocytes and C6 glioma cells to secrete mitogenic growth factors.
In this study, the effect of thyroid hormone (triiodothyronine, T(3)) on the secretion of mitogenic growth factors in astrocytes and C6 glioma cells was examined. The proliferating activity of T(3) could be due, at least in part, to the astrocyte secretion of acidic and basic fibroblast growth factor (aFGF and bFGF), tumor necrosis factor-beta, and transforming growth factor-beta. In contrast, the conditioned medium (CM) of T(3)-treated C6 cells was mitogenic to this cell line only after hyaluronidase digestion, suggesting the impairment of growth factor mitogenic activity by hyaluronic acid. Furthermore, the presence of bFGF was significantly greater in the CM of both T(3)-treated astrocytes and T(3)-treated C6 cells than in the corresponding control CM. These data show that T(3) induces cerebellar astrocytes to secrete mitogenic growth factors, predominantly bFGF, that could influence astrocyte and neuronal proliferation via autocrine and paracrine pathways.
Trentin
A G
AG
Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, Santa Catarina, Brazil.
Alvarez-Silva
M
M
Moura Neto
V
V
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology*; D017077:Culture Media, Conditioned; D016220:Fibroblast Growth Factor 1 / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006133:Growth Substances / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology; D006820:Hyaluronic Acid / Q000494:pharmacology; D006821:Hyaluronoglucosaminidase / Q000378:metabolism; D008233:Lymphotoxin-alpha / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014284:Triiodothyronine / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D017077:Culture Media, Conditioned; D006133:Growth Substances; D008233:Lymphotoxin-alpha; D016212:Transforming Growth Factor beta; D014284:Triiodothyronine; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1; D006820:Hyaluronic Acid; D006493:Heparin; D006821:Hyaluronoglucosaminidase