IN VITRO THYROID HORMONE–DISRUPTING ACTIVITY IN EFFLUENTS AND SURFACE WATERS IN THAILAND

2009 ◽  
Vol 28 (3) ◽  
pp. 586 ◽  
Author(s):  
Akinori Ishihara ◽  
Farhana B. Rahman ◽  
Ladda Leelawatwattana ◽  
Porntip Prapunpoj ◽  
Kiyoshi Yamauchi
Keyword(s):  
Thyroid Hormone ◽  
Surface Waters

scholarly journals Influence of thyroid hormone on the in vitro translational activity of specific mRNAs in the rat heart.

1983 ◽  
Vol 258 (12) ◽  
pp. 7738-7745 ◽  
Author(s):  
W H Dillmann ◽  
A Barrieux ◽  
W E Neeley ◽  
P Contreras
Keyword(s):  
Thyroid Hormone ◽  
Rat Heart ◽  
Translational Activity ◽  
Specific Mrnas

scholarly journals Desethylamiodarone antagonizes the effect of thyroid hormone at the molecular level

2001 ◽  
pp. 59-64 ◽  
Author(s):  
F Bogazzi ◽  
L Bartalena ◽  
S Brogioni ◽  
A Burelli ◽  
F Raggi ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Molecular Mechanisms ◽  
Thyroid Hormone Receptor ◽  
Molecular Level ◽  
Inhibitory Effect ◽  
Mobility Shift ◽  
Down Regulation ◽  
Nih3t3 Cells ◽  
Peripheral Tissues

OBJECTIVE: To evaluate the molecular mechanisms of the inhibitory effects of amiodarone and its active metabolite, desethylamiodarone (DEA) on thyroid hormone action. MATERIALS AND METHODS: The reporter construct ME-TRE-TK-CAT or TSHbeta-TRE-TK-CAT, containing the nucleotide sequence of the thyroid hormone response element (TRE) of either malic enzyme (ME) or TSHbeta genes, thymidine kinase (TK) and chloramphenicol acetyltransferase (CAT) was transiently transfected with RSV-TRbeta into NIH3T3 cells. Gel mobility shift assay (EMSA) was performed using labelled synthetic oligonucleotides containing the ME-TRE and in vitro translated thyroid hormone receptor (TR)beta. RESULTS: Addition of 1 micromol/l T4 or T3 to the culture medium increased the basal level of ME-TRE-TK-CAT by 4.5- and 12.5-fold respectively. Amiodarone or DEA (1 micromol/l) increased CAT activity by 1.4- and 3.4-fold respectively. Combination of DEA with T4 or T3 increased CAT activity by 9.4- and 18.9-fold respectively. These data suggested that DEA, but not amiodarone, had a synergistic effect with thyroid hormone on ME-TRE, rather than the postulated inhibitory action; we supposed that this was due to overexpression of the transfected TR into the cells. When the amount of RSV-TRbeta was reduced until it was present in a limited amount, allowing competition between thyroid hormone and the drug, addition of 1 micromol/l DEA decreased the T3-dependent expression of the reporter gene by 50%. The inhibitory effect of DEA was partially due to a reduced binding of TR to ME-TRE, as assessed by EMSA. DEA activated the TR-dependent down-regulation by the negative TSH-TRE, although at low level (35% of the down-regulation produced by T3), whereas amiodarone was ineffective. Addition of 1 micromol/l DEA to T3-containing medium reduced the T3-TR-mediated down-regulation of TSH-TRE to 55%. CONCLUSIONS: Our results demonstrate that DEA, but not amiodarone, exerts a direct, although weak, effect on genes that are regulated by thyroid hormone. High concentrations of DEA antagonize the action of T3 at the molecular level, interacting with TR and reducing its binding to TREs. This effect may contribute to the hypothyroid-like effect observed in peripheral tissues of patients receiving amiodarone treatment.

A battery of in vivo and in vitro tests useful for genotoxic pollutant detection in surface waters

2006 ◽  
Vol 77 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Claudia Pellacani ◽  
Annamaria Buschini ◽  
Mariangela Furlini ◽  
Paola Poli ◽  
Carlo Rossi
Keyword(s):  
Surface Waters ◽  
In Vitro Tests ◽  
Pollutant Detection

Ligand-dependent, Pit-1/growth hormone factor-1 (GHF-1)-independent transcriptional stimulation of rat growth hormone gene expression by thyroid hormone receptors in vitro

1993 ◽  
Vol 13 (3) ◽  
pp. 1719-1727
Author(s):  
C S Suen ◽  
W W Chin
Keyword(s):  
Gene Expression ◽  
Growth Hormone ◽  
Thyroid Hormone ◽  
Promoter Activity ◽  
Hormone Receptors ◽  
Nuclear Extract ◽  
In Vitro Transcription ◽  
Stimulation Of ◽  
Transcriptional Stimulation

The expression of the rat growth hormone (rGH) gene in the anterior pituitary gland is modulated by Pit-1/GHF-1, a pituitary-specific transcription factor, and by other more widely distributed factors, such as the thyroid hormone receptors (TRs), Sp1, and the glucocorticoid receptor. Thyroid hormone (T3)-mediated transcriptional stimulation of rGH gene expression has been extensively studied in vivo and in vitro including the measurements of (i) rGH mRNA by blot hybridization, (ii) transcriptional rate of rGH gene by nuclear run-on, and (iii) reporter gene expression in which a chimeric plasmid containing 5'-flanking sequences of the rGH gene linked to a reporter gene has been transfected either stably or transiently into pituitary and/or nonpituitary cells. From these studies, it has been suggested that the Pit-1/GHF-1 binding site is necessary for full T3 action. We developed a cell-free in vitro transcription system to examine further the roles of the TRs and Pit-1/GHF-1 in rGH gene activation. Using GH3 nuclear extract as a source of TRs and Pit-1/GHF-1, this in vitro transcription assay showed that T3 stimulation of rGH promoter activity is dependent on the addition of T3 to the GH3 nuclear extract. This transcriptional stimulation was augmented with increasing concentrations of ligand and was T3, but not T4 or reverse T3, specific. T3-mediated stimulation of rGH promoter activity was completely abolished by preincubation of the nuclear extract with rGH-thyroid hormone response element (-200 to -160) but not with Pit-1/GHF-1 (-137 to -65) oligonucleotides. Further, neither deletion of both Pit-1/GHF-1 binding sites nor mutation of the proximal Pit-1/GHF-1 binding site from the rGH promoter abrogated the T3 effect. These results provide evidence that T3-stimulated rGH promoter activity is independent of Pit-1/GHF-1 and raise the possibility that the stimulation of rGH gene expression by T3 might involve direct interaction of TRs with the general transcriptional apparatus.

Thyroid hormone deficiency changes the distribution of oligodendrocyte/myelin markers during oligodendroglial differentiation in vitro

2006 ◽  
Vol 24 (7) ◽  
pp. 445-453 ◽  
Author(s):  
V. Younes‐Rapozo ◽  
J. Berendonk ◽  
T. Savignon ◽  
A.C. Manhães ◽  
P.C. Barradas
Keyword(s):  
Thyroid Hormone ◽  
Hormone Deficiency

Thyroid hormone as a biological amplifier of differentiated trophoblast function in early pregnancy

1991 ◽  
Vol 125 (1) ◽  
pp. 58-66 ◽  
Author(s):  
Takeshi Maruo ◽  
Hiroya Matsuo ◽  
Matsuto Mochizuki
Keyword(s):  
Thyroid Hormone ◽  
Early Pregnancy ◽  
Direct Consequence ◽  
Endocrine Function ◽  
Aromatase Activity ◽  
Maximum Increase ◽  
Stimulatory Action ◽  
Endocrine Activity ◽  
Estradiol 17Β

Abstract. Direct effects of T3 or T4 on the trophoblast function were investigated in vitro using an organ culture system of human placental tissues. Explants of trophoblastic tissues obtained from normal early and term placentas were cultured with or without graded doses of T3 or T4 for 5 days in a serum-free condition. Addition of T3 (10−8 mol/l) resulted in the maximum increase in daily secretion of progesterone, estradiol-17β as well as hCGα, hCGβ, hCG and hPL by cultured early placental tissues. Increases in progesterone and estradiol-17β secretion caused by the addition of T3 were further augmented in response to concomitant addition of pregnenolone and testosterone, respectively, suggesting that T3 (10−8 mol/l) enhances 3β-hydroxysteroid dehydrogenase and aromatase activity in the placenta. These stimulatory effects of T3 (10−8 mol/l) on the trophoblast endocrine function were also found with the use of T4 (10−7 mol/l). Addition of higher or lower concentrations of T3 or T4 gave attenuated effects. These results suggest that the optimal concentration of thyroid hormone is needed for it to exert its maximally stimulatory action on trophoblast endocrine function. Unlike early placental tissues, cultured term placental tissues did not respond to the addition of T3 or T4 with increased endocrine activity. Thus, the frequent occurrence of spontaneous abortion in early pregnancy during the state of hypothyroidism or hyperthyroidism may represent a direct consequence of inadequate thyroid hormone availability at the level of placental trophoblasts, followed by diminished expression of trophoblast endocrine function.

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