Triiodothyronine Rapidly Alters the TSH Content and the Secretory Granules Distribution in Male Rat Thyrotrophs by a Cytoskeleton Rearrangement-Independent Mechanism

Autor(es)

Bargi-Souza, Paula ^[1] ; Romano, Renata Marino ^[1] ; Salgado, Renato de Mayrinck ^[2] ; Goulart-Silva, Francemilson ^[1] ; Brunetto, Erika Lia ^[1] ; Tenorio Zorn, Telma Maria ^[2] ; Nunes, Maria Tereza ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05508900 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Biomed Sci, Dept Cell & Dev Biol, BR-05508900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Endocrinology; v. 154, n. 12, p. 4908-4918, DEC 2013.
• Citações Web of Science: 14

Resumo

Rapid actions of T-3 on TSH synthesis in posttranscriptional steps, such as polyadenylation and translation rate, have already been described. The focus of this paper was to characterize rapid actions of T-3 on TSH secretion and the involvement of actin and microtubule cytoskeleton in this process. For that, sham-operated (SO) and thyroidectomized (Tx) rats were subjected to acute or chronic treatment with T-3. We observed a disarrangement in microtubule and actin cytoskeletons and an increase in Tshb mRNA levels in Tx rats, whereas the total TSH protein content was reduced in the pituitary gland as a whole, but increased in the secretory granules close to the plasma membrane of thyrotrophs, as well as in the extracellular space. The acute T-3 dose promoted a rapid increase and redistribution of TSH secretory granules throughout the cytoplasm, as well as a rearrangement in actin and microtubule cytoskeletons. The T-3 chronic treatment outcome reinforces the acute effects observed and, additionally, evinces an increase in the alpha-tubulin content and a rearrangement in microtubule cytoskeleton. Thus, T-3 is able to rapidly suppress TSH secretion and, in parallel, to promote a rearrangement in actin and microtubules assembly throughout the pituitary gland, effects that seem to be independent from each other. (AU)

• Processo FAPESP: 06/61713-0 - Acoes nao genomicas dos hormonios tireoideanos na hipofise de ratos: repercussoes na sintese e secrecao de hormonio do crescimento (gh) e tireotrofico (tsh).
• Beneficiário: Maria Tereza Nunes
• Modalidade de apoio: Auxílio à Pesquisa - Regular