Effect of thyroid hormone on T3-receptor mRNA levels and growth of thyrotropic tumors.
Mol Cell Endocrinol
; 91(1-2): 75-81, 1993 Feb.
Article
em En
| MEDLINE
| ID: mdl-8472856
ABSTRACT
Thyrotropic tumors (TtT97) contain mRNA transcripts for three T3-receptor (TR) isoforms, alpha 1, beta 1 and beta 2, and a non-receptor alpha 2-variant. We administered T4 (5 mg/l of drinking water) for one month to TtT97-bearing mice, to examine its effect on tumor growth and tumor TR isoform steady-state mRNA levels. Baseline mice were killed at the start of the experiment, and placebo mice were maintained hypothyroid. The treated tumors were 30-35% smaller than the baseline tumors (p = NS), while the placebo tumors were 2- to 7-fold larger than the baseline tumors (p < 0.05). TR beta 1 mRNA increased 5- to 6-fold, while TR beta 2 mRNA decreased by 76%. TR alpha 1 and the alpha 2-variant decreased by 52% and 70%, respectively. Therefore, the tumors decreased their growth rate in response to T4 administration, and increased the ratio of TR beta 1 to TR beta 2 mRNA. This raises the intriguing possibility of a correlation between the relative abundance of the TR beta isoforms and tumor growth.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Hipofisárias
/
Tiroxina
/
Receptores dos Hormônios Tireóideos
/
RNA Mensageiro
/
Tireotropina
Limite:
Animals
Idioma:
En
Revista:
Mol Cell Endocrinol
Ano de publicação:
1993
Tipo de documento:
Article