Thyrotroph
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Non genomic actions of triiodothyronine (T3) on the expression polyadenylation and distribution of TSH granules in thyrotrophs of hypothyroid rats / Ações não genômicas da triiodotironina (T3) sobre a expressão, poliadenilação e distribuição dos grânulos de TSH nos tireotrofos de ratos hipotireiodeos
The thyroid-stimulating hormone (TSH) is the main regulator of the synthesis and secretion of thyroid hormones (TH), which exert a negative feedback mechanism in the pituitary by reducing the synthesis of β and α (CGA - Glycoprotein hormones alpha chain) chains through mechanisms that involve changes in the tra
Publicado em: 2010
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2. Morphometric and ultrastructural analysis of different pituitary cell populations in undernourished monkeys
Undernutrition elicited by a low-protein diet determines a marked reduction of hypophyseal activity and affects the function of the respective target organs. The objective of the present investigation was to study the ultrastructural and quantitative immunohistochemical changes of the different pituitary cell populations in undernourished monkeys that had be
Brazilian Journal of Medical and Biological Research. Publicado em: 2001-01
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3. Seasonal changes in the ultrastructure of the thyrotroph in the wookchuck (Marmota monax) adenohypophysis.
Throtrophs of the woodchuck anterior pituitary are described through the four seasons of the year. Evidence of an increase in number and activity in the spring is presented. Activity of the thyrotroph is seen to continue through the summer and decline in the autumn to quiescence during the hibernatory period of winter. The significance of these findings is d
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4. Rapid alteration in circulating free thyroxine modulates pituitary type II 5' deiodinase and basal thyrotropin secretion in the rat.
TSH secretion is decreased by both T4 and T3. This negative feedback control of TSH secretion has been correlated with an increase in pituitary nuclear T3 content, and it is not clear whether T4 exerts its effect directly on the thyrotroph or after its deiodination to T3. However, levels of the pituitary enzyme catalyzing T4 to T3 conversion, 5'D-II, are dec
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5. Role of a pituitary-specific transcription factor (pit-1/GHF-1) or a closely related protein in cAMP regulation of human thyrotropin-beta subunit gene expression.
cAMP regulation of the human thyrotropin-beta (TSH beta) gene cAMP was studied in two heterologous cell lines, a human embryonal kidney cell line (293) and a rat pituitary cell line (GH3). In 293 cells, human TSH beta gene expression was not stimulated by the adenylate cyclase activator forskolin or the cAMP analogue 8-bromo-cAMP (8-Br-cAMP). On the other ha
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6. A soluble transcription factor, Oct-1, is also found in the insoluble nuclear matrix and possesses silencing activity in its alanine-rich domain.
Expression of the human thyrotropin beta (hTSHbeta) gene is restricted to thyrotrophs, at least in part, by silencing. Using transient-transfection assays, we have localized a silencer element to a region between -128 and -480 bp upstream of the transcription initiation site. The silencing activity was overcome in a thyrotroph-specific manner by an unknown e
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7. The loss of circadian PAR bZip transcription factors results in epilepsy
DBP (albumin D-site-binding protein), HLF (hepatic leukemia factor), and TEF (thyrotroph embryonic factor) are the three members of the PAR bZip (proline and acidic amino acid-rich basic leucine zipper) transcription factor family. All three of these transcriptional regulatory proteins accumulate with robust circadian rhythms in tissues with high amplitudes
Cold Spring Harbor Laboratory Press.
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8. Thyrotropin-releasing hormone regulation of human TSHB expression: role of a pituitary-specific transcription factor (Pit-1/GHF-1) and potential interaction with a thyroid hormone-inhibitory element.
Regulation of human thyrotropin beta subunit gene (TSHB) expression by thyrotropin-releasing hormone (TRH) was examined in a clonal rat pituitary-cell line (GH3). Transient expression studies were done with various 5'-flanking DNA sequences of TSHB coupled to reporter gene chloramphenicol acetyltransferase. Deletion analysis defined two discrete regions (-12
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9. Novel insight from transgenic mice into thyroid hormone resistance and the regulation of thyrotropin
Patients with resistance to thyroid hormone (RTH) exhibit elevated thyroid hormone levels and inappropriate thyrotropin (thyroid-stimulating hormone, or TSH) production. The molecular basis of this disorder resides in the dominant inhibition of endogenous thyroid hormone receptors (TRs) by a mutant receptor. To determine the relative contributions of pituita
American Society for Clinical Investigation.
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10. Changes in the sialylation and sulfation of secreted thyrotropin in congenital hypothyroidism.
We have examined the oligosaccharide structure of secreted thyrotropin (TSH) in perinatal and mature rats with congenital primary hypothyroidism. Rat pituitaries from euthyroid control animals and those rendered hypothyroid by methimazole treatment were incubated with [3H]glucosamine in vitro. Secreted TSH was purified, and oligosaccharides were enzymaticall
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11. Cell transformation mediated by homodimeric E2A-HLF transcription factors.
The E2A-HLF fusion gene, created by the t(17;19)(q22;p13) chromosomal translocation in pro-B lymphocytes, encodes an oncogenic protein in which the E2A trans-activation domain is linked to the DNA-binding and protein dimerization domain of hepatic leukemia factor (HLF), a member of the proline- and acidic amino acid-rich (PAR) subfamily of bZIP transcription
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12. Role of neuromedin B in the control of the release of thyrotropin in the rat.
Neuromedin B (NB), a bombesin-like peptide, was first isolated from porcine spinal cord and subsequently found in the central nervous systems of rat, cat, and human. Immunocytochemical studies have shown that NB is present in hypothalamus and various other regions of the brain and in thyrotrophs of the anterior pituitary of the rat. The possible physiologica