| Registro completo |
| Provedor de dados: |
BJMBR
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| País: |
Brazil
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| Título: |
Pituitary-thyroid axis in short- and long-term experimental diabetes mellitus
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| Data: |
1997-02-01
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| Ano: |
1997
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| Palavras-chave: |
Thyroid
Pituitary
Diabetes mellitus
T4-5'-deiodinase
Serum T4
Serum TSH
Rat
Streptozotocin
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| Resumo: |
Short-term experimental diabetes mellitus (DM) produces a significant decrease in serum thyroid hormones, a decreased or normal serum thyroid-stimulating hormone (TSH) and a reduction in hepatic and renal T4-5'-deiodination. However, little is known about the effects of chronic diabetes mellitus on the pituitary-thyroid axis function. We evaluated the changes induced by very short-term (6 days), short-term (15 days) and chronic (6 months) streptozotocin-induced diabetes mellitus in 3-month old female Dutch-Miranda rat serum T4, serum TSH and T4-5'-deiodinase activity in the thyroid and pituitary glands. Serum hormones were determined by specific radioimmunoassays. Iodothyronine-5'-deiodinase activities were assayed in the thyroid and pituitary microsomal fractions using 2 µM T4 as substrate. Mean serum T4 was significantly decreased from 3.3 to 2.0 µg/dl 6 days after diabetes mellitus induction, and from 2.2 to 1.5 µg/dl after 15 days of DM, with no significant changes in serum TSH, indicating a decreased pituitary TSH responsiveness to the diminished suppression by T4, even though pituitary T4-5'-deiodinase activity was unchanged. Thyroid T4-5'-deiodinase was unchanged after 6 days of diabetes mellitus, but was significantly increased from 20.6 to 37.0 pmol T3/mg protein after 15 days. Six months after diabetes mellitus induction, both serum T4 and thyroid T4-5'-deiodinase returned to normal ranges and serum TSH was unchanged, although pituitary T4-5'-deiodinase was now significantly decreased from 2.7 to 1.7 pmol T3/mg protein. These findings indicate that some kind of adaptation to chronic insulinopenia may occur at the thyroid level, but this does not seem to be true for the pituitary
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| Tipo: |
Info:eu-repo/semantics/other
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000200017
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| Editor: |
Associação Brasileira de Divulgação Científica
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| Relação: |
10.1590/S0100-879X1997000200017
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| Formato: |
text/html
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| Fonte: |
Brazilian Journal of Medical and Biological Research v.30 n.2 1997
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| Direitos: |
info:eu-repo/semantics/openAccess
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