Os hormônios tireoideanos e o desenvolvimento esquelético fetal e pós-natal: estudo do padrão de expressão dos transportadores e das selenodesiodases das iodotironinas. / Thyroid hormone and skeletal development at fetal and postnatal ages: the expression pattern of iodothyronine transporters and deiodinases.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Thyroid hormone (TH) plays a key role on post-natal bone development and metabolism, while its relevance during fetal bone development is uncertain. To study this, pregnant mice and fetuses were made hypothyroid. The skeleton morphology was preserved up to 16.5 embryonic days (E). Only at E18.5, the hypothyroid fetuses exhibited a reduction in femoral type I and type X collagen and osteocalcin mRNA levels, in the length and area of the proliferative and hypertrofic zones, in the number of chondrocytes per proliferative column, and in the number of hypertrophic chondrocytes. This suggests that up to E16.5, thyroid hormone signaling in bone is kept to a minimum. D3 mRNA was readily detected as early as E14.5 and its expression decreased markedly at E18.5, and even more after birth. The expression levels of D3 gene during early bone development along with the absence of a hypothyroidism-induced bone phenotype at this time suggest that its expression keeps thyroid hormone signaling in bone to very low levels at this early stage of bone development.

ASSUNTO(S)

boné development selenodesiodase das iodotironinas do tipo 2 congenital hypothyroidism monocarboxilate transporter 8 deiodinase type 3 desenvolvimento ósseo transportador de monocarboxílicos thyroid hormone selenodesiodase das iodotironinas do tipo 3 hormônios tireoideanos deiodinase type 2 hipotireoidismo

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