Thyrotropin
Mostrando 25-36 de 325 artigos, teses e dissertações.
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25. Estradiol decreases iodide uptake by rat thyroid follicular FRTL-5 cells
Estradiol has well-known indirect effects on the thyroid. A direct effect of estradiol on thyroid follicular cells, increasing cell growth and reducing the expression of the sodium-iodide symporter gene, has been recently reported. The aim of the present investigation was to study the effect of estradiol on iodide uptake by thyroid follicular cells, using FR
Brazilian Journal of Medical and Biological Research. Publicado em: 2001-02
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26. Tratamento do hipertireoidismo na infância e adolescência
A Doença de Graves (DG) é responsável por mais de 90% dos casos de hipertireoidismo em crianças. Na DG, o hipertireoidismo é causado por anticorpos estimuladores dirigidos contra o receptor do TSH, conhecidos como TRAb (TRAb, Thyrotropin Receptor Antibody), que mimetizam os efeitos do TSH. O hipertireoidismo pode, ainda, ser devido a mutações nos gene
Arquivos Brasileiros de Endocrinologia & Metabologia. Publicado em: 2001-02
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27. Effect of medroxyprogesterone acetate on thyrotropin secretion in adult and old female rats
Steroid hormones have been implicated in the modulation of TSH secretion; however, there are few and controversial data regarding the effect of progesterone (Pg) on TSH secretion. Medroxyprogesterone acetate (MPA) is a synthetic alpha-hydroxyprogesterone analog that has been extensively employed in therapeutics for its Pg-like actions, but that also has some
Brazilian Journal of Medical and Biological Research. Publicado em: 2000-09
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28. Synthesis, cloning, and identification of DNA sequences complementary to mRNAs for alpha and beta subunits of thyrotropin.
Double-stranded cDNA sequences were synthesized, by using as templates mRNA for alpha and beta subunits of thyrotropin purified from mouse thyrotrophic pituitary tumours and cloned in Escherichia coli RR1 by insertion in the Pst I site of the bacterial plasmid pBR322 by use of poly(dA) x poly(dT) homopolymeric extensions. Plasmids containing inserted cDNA se
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29. Cholera toxin interactions with thyrotropin receptors on thyroid plasma membranes.
Unlabeled cholera toxin inhibits [125I]thyrotropin binding to thyrotropin receptors on thyroid plasma membranes. Maximal inhibition by cholera toxin does not exceed 40%, whereas unalbeled thyrotropin completely inhibits [125I]thyrotropin binding to these same membranes. Kinetic analyses of the binding data are compatible with the view that the cholera toxin
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30. Monoclonal antibodies to the thyrotropin receptor: implications for receptor structure and the action of autoantibodies in Graves disease.
Hybridoma cells have been obtained by fusing P3-NS1/1-Ag4-1 mouse myeloma cells with spleen cells from mice immunized with solubilized preparations of the thyrotropin receptor. Five clones were produced that secrete a monoclonal antibody whose binding to thyroid membranes is specifically inhibited by unlabeled thyrotropin. The antibody interacts with functio
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31. Thyrotropin stimulation of the ADP-ribosyltransferase activity of bovine thyroid membranes.
Thyrotropin increases the ADP-ribosylation activity of bovine thyroid membranes. Rapid ADP-ribosylation of membrane components is followed by increasing ADP-ribosylation of components in the supernatant of the reaction mixture. One of the major membrane proteins ADP-ribosylated in the thyrotropin-stimulated reaction has an approximate molecular weight of 40,
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32. Monoclonal antibodies to the thyrotropin receptor: stimulating and blocking antibodies derived from the lymphocytes of patients with Graves disease.
Human monoclonal antibodies have been generated from heterohybridomas obtained by fusing mouse myeloma cells with peripheral lymphocytes from patients with active Graves disease. This report characterizes four antibodies as presumptive thyrotropin receptor antibodies because they specifically inhibit thyrotropin binding and competitively inhibit thyrotropin-
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33. Thyrotropin-ganglioside interactions and their relationship to the structure and function of thyrotropin receptors.
Gangliosides inhibit 125I-labeled thyrotropin binding to the thyrotropin receptors on bovine thyroid plasma membranes, on guinea pig retro-orbital tissue plasma membranes, and on human adipocyte membranes. This inhibition by gangliosides is critically altered by the number and location of the sialic acid residues within the ganglioside structure, the efficac
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34. Increased sensitivity of the thyroid in iodine-depleted rats to the goitrogenic effects of thyrotropin
The present studies demonstrate that iodine depletion increases the sensitivity of the thyroid to the goitrogenic effects of thyrotropin. Iodine depletion was induced by feeding rats a low iodine diet containing propylthiouracil for 10-14 days before hypophysectomy. Accumulation of iodine in the thyroid after hypophysectomy was prevented by continuing the an
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35. Relationship of gangliosides to the structure and function of thyrotropin receptors: their absence on plasma membranes of a thyroid tumor defective in thyrotropin receptor activity.
Plasma membranes derived from rat thyroid tumor (1-8R) which is unresponsive to thyrotropin but is responsive to dibutyryl adenosine 3':5'-cyclic monophosphate bind less than 20% of the [125I] thyrotropin which can be bound to plasma membranes from normal rat thyroids under conditions which optimize tumor membrane binding relative to normal thyroid membranes
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36. Effects of thyrotropin on the thyroid cell membrane: Hyperpolarization induced by hormone-receptor interaction
Cultured thyroid cells accumulate the lipophilic cation triphenylmethylphosphonium, indicating that there is an electrical potential (interior negative) across the plasma membrane. Thyrotropin stimulates the uptake of the lipophilic cation 3-fold, and the proton conductor carbonylcyanide-m-chlorophenylhydrazone causes efflux of triphenylmethylphosphonium acc