Search results for " Thyroid Hormone"
showing 10 items of 19 documents
Homozygous Resistance to Thyroid Hormone β: Can Combined Antithyroid Drug and Triiodothyroacetic Acid Treatment Prevent Cardiac Failure?
2017
Resistance to thyroid hormone β (RTHβ) due to homozygous THRB defects is exceptionally rare, with only five kindreds reported worldwide. Cardiac dysfunction, which can be life-threatening, is recognized in the disorder. Here we describe the clinical, metabolic, ophthalmic, and cardiac findings in a 9-year-old boy harboring a biallelic THRB mutation (R243Q), along with biochemical, physiologic, and cardiac responses to carbimazole and triiodothyroacetic acid (TRIAC) therapy. The patient exhibits recognized features (goiter, nonsuppressed thyroid-stimulating hormone levels, upper respiratory tract infections, hyperactivity, low body mass index) of heterozygous RTHβ, with additional characteri…
Effects of 3,5-diiodo-L-thyronine on the liver of high fat diet fed rats
2016
Experimental studies have highlighted that the administration of 3,5-diiodo-L-thyronine (T2) to rats fed diets rich in lipids induces a decrease of cholesterol and triglycerides plasma levels and body weight (BW) without inducing liver steatosis. On the basis of these observations we carried out some experimental <em>in vivo</em> studies to assess the effects of multiple high doses of T2 on the pituitary thyroid axis of rats fed diet rich in lipids. Fifteen male Wistar rats were divided into three groups of five animals each. The first group (N group) received standard diet, the second group was fed with a high fat diet (HFD group), while the third group (HFDT2 group) was additi…
Genomic and non-genomic mechanisms of action of thyroid hormones and their catabolite 3,5-diiodo-l-thyronine in Mammals
2020
Since the realization that the cellular homologs of a gene found in the retrovirus that contributes to erythroblastosis in birds (v-erbA), i.e. the proto-oncogene c-erbA encodes the nuclear receptors for thyroid hormones (THs), most of the interest for THs focalized on their ability to control gene transcription. It was found, indeed, that, by regulating gene expression in many tissues, these hormones could mediate critical events both in development and in adult organisms. Among their effects, much attention was given to their ability to increase energy expenditure, and they were early proposed as anti-obesity drugs. However, their clinical use has been strongly challenged by the concomita…
RORgamma-expressing Th17 cells induce murine chronic intestinal inflammation via redundant effects of IL-17A and IL-17F.
2008
Background and Aims IL-17–producing CD4 + T-helper cells (Th17) contribute to chronic autoimmune inflammation in the brain, and levels of Th17-derived cytokines increase in patients with colitis, suggesting a role in pathogenesis. We analyzed the roles of Th17 cells and the transcription factor retinoic acid receptor-related organ receptor (ROR)γ, which regulates Th17 differentiation, in chronic intestinal inflammation. Methods Using an adoptive transfer model of colitis, we compared the colitogenic potential of wild-type, interleukin-17A (IL-17A)–, IL-17F–, IL-22–, and RORγ-deficient CD4 + CD25 − T cells in RAG1-null mice. Results Adoptive transfer of IL-17A–, IL-17F–, or IL-22–deficient T…
Phenotypic variability in patients with generalised resistance to thyroid hormone.
1995
Genetic linkage of generalised resistance to thyroid hormone (GRTH) to the human thyroid receptor beta 1 gene has been identified. To date 38 different mutations in several kindreds have been documented. We report on a family with GRTH displaying an adenine for guanine substitution at nucleotide 1234 resulting in a threonine for alanine substitution at codon 317 of exon 9. This mutation has been described for different phenotypes, suggesting that the heterogeneity in GRTH may be the result of multiple genetic factors.
Cellular mechanism of action of thyroid hormones.
1987
Abstract It has emerged in the last decade that the molecular mechanism of action of thyroid hormones resembles that of steroids; thyroid hormones indeed exert their effects mainly by directly regulating gene expression, on association with specific chromatin-bound receptors. Of the two thyroid hormones, thyroxine (T4) appears to be a sort of prohormone, whereas triiodothyronine (T3) seems to be the active form; in this respect, T4-deiodination, which occurs at the level of the target tissues, may be crucial in the local homeostasis of T3. Moreover, many cellular compartments, other than the nucleus, can bind thyroid hormone, and at least some of these further sites might play some role in …
Nuclear receptors modulate the interaction of Sp1 and GC-rich DNA via ternary complex formation
2000
Binding sites for transcription factor Sp1have been implicated in the transcriptional regulation of several genes by hormones or vitamins, and here we show that a GC-rich element contributes to the retinoic acid response of the interleukin 1β promoter. To explain such observations, it has been proposed that nuclear receptors can interact with Sp1 bound to GC-rich DNA. However, evidence supporting this model has remained indirect. So far, nuclear receptors have not been detected in a complex with Sp1 and GC-rich DNA, and the expected ternary complexes in non-denaturing gels were not seen. In search for these missing links we found that nuclear receptors [retinoic acid receptor (RAR), thyroid…
T helper 17 lineage differentiation is programmed by orphan nuclear receptors ROR alpha and ROR gamma.
2007
T cell functional differentiation is mediated by lineage-specific transcription factors. T helper 17 (Th17) has been recently identified as a distinct Th lineage mediating tissue inflammation. Retinoic acid receptor-related orphan receptor gamma (ROR gamma) was shown to regulate Th17 differentiation; ROR gamma deficiency, however, did not completely abolish Th17 cytokine expression. Here, we report Th17 cells highly expressed another related nuclear receptor, ROR alpha, induced by transforming growth factor-beta and interleukin-6 (IL-6), which is dependent on signal transducer and activator of transcription 3. Overexpression of ROR alpha promoted Th17 differentiation, possibly through the c…
Resistance to thyroid hormones. Study of an affected kindred diagnosed at neonatal age
1998
Resistance to thyroid hormones (RTH) is a rare condition of reduced activity of thyroid hormones on peripheral tissues and/or reduced suppression of TSH secretion by thyroid hormones. The disease is characterised by high serum levels of T3, T4, fT3 and fT4, and by unexpectedly normal or high TSH levels. The origin of the resistance has been recognised in a thyroid hormone receptor deficit, whose gene (TRβ) has been mapped on chromosome 3p24.3 and several mutations have been identified. The clinical presentation may vary among a large spectrum from hypo-, to eu-, to hyperthyroidism in different patients, even in the same family. The diagnosis of RTH at birth and in the first months of life i…
Metabolic adaptations in neonatal mother-deprived rabbits
2010
[EN] In order to study the metabolic adaptation in response to 48 h transient doe-litter separation (DLS) in young rabbits (5 rabbits/d group) between postnatal 9 and 11 d, plasma concentrations of thyroid hormones T3 and T4, insulin, leptin, glucose, triglycerides (TG), and free fatty acids (FFA) were examined before (6-8 d), during (9-11 d), and after separation (12-16 d). T3 concentrations in newborn control rabbits gradually increased from 0.6 ng/mL at postnatal 6 d to 1.0 ng/mL at postnatal 16 d, whereas those of T4 remained fairly constant (25 ng/mL) up to postnatal 14 d, when T4 gradually declined to 8 ng/mL. T3 values of DLS newborn rabbits did not differ from those of controls at p…