TRIIODOTHYRONINE BINDING TO LYMPHOCYTES FROM EUTHYROID SUBJECTS AND A PATIENT WITH PERIPHERAL RESISTANCE TO THYROID HORMONE

1976 ◽  
Vol 83 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Kristian Liewendahl
Keyword(s):  
Thyroid Hormone ◽  
Binding Sites ◽  
Binding Capacity ◽  
Human Lymphocytes ◽  
Peripheral Resistance ◽  
Subsequent Treatment ◽  
Affinity Constant ◽  
Prolonged Incubation ◽  
Resistance To Thyroid Hormone ◽  
The Mean

ABSTRACT Triiodothyronine (T3) binding to Ficoll-Isopaque purified human lymphocytes was studied. During incubation of lymphocytes with [125I]T3 in a calcium-free medium at 37°C, maximal uptake of T3 in nuclei occurred after 2 h and declined after prolonged incubation. Incubation of lymphocytes with T3 concentrations ranging from 1 × 10−11 to 1 × 10−9 mol/l and subsequent treatment with Triton X-100 to strip off [125I]T3 bound with low affinity was used for the estimation of affinity and capacity of nuclear T3 binding sites. The mean equilibrium affinity constant (Ka) estimated with the Scatchard method in 11 euthyroid healthy subjects was 4.5 × 109 1/mol, and the mean maximal binding capacity 25 × 10−15 mol/100 μg DNA. In a female patient with peripheral resistance to thyroid hormone action, the estimated Ka was 3.5 × 109 1/mol and the number of T3 binding sites 37 × 10−15 mol/100 μg DNA. Although not statistically different from the mean value in euthyroid subjects, this Ka value was outside the range of control values observed and was considered presumptive evidence that the nuclear T3 receptors in this patient have abnormally low affinity for its ligand. The nuclear T3 binding capacity in this patient was significantly increased.

Triiodothyronine binding to lymphocyte nuclei and plasma cyclic AMP response to intravenous glucagon in patients with peripheral resistance to thyroid hormones

1981 ◽  
Vol 97 (1) ◽  
pp. 54-59 ◽  
Author(s):  
A. Elewaut ◽  
M. De Baets ◽  
A. Vermeulen
Keyword(s):  
Thyroid Hormone ◽  
Cyclic Amp ◽  
Binding Capacity ◽  
Peripheral Resistance ◽  
Resistance To Thyroid Hormone ◽  
Binding Characteristics ◽  
Nuclear Binding ◽  
Resistance To Thyroid Hormones ◽  
The Family

Abstract. In vitro studies of nuclear binding of triiodothyronine (T3) in lymphocytes were performed in three members of a family with hereditary peripheral resistance to thyroid hormone action. Ficoll-Hypaque® purified lymphocytes were used; the binding characteristics were analyzed by Scatchard's methods. In 5 euthyroid subjects the apparent mean equilibrium association constant (Ka) was 6.1 × 109 1/mol and the mean maximal binding capacity (Cap) 14.4 × 10−15 mol/ 100 μg DNA. In the 3 members of the family one single set of saturable T3 nuclear binding sites with affinity constants similar to those in the controls (mean Ka = 3.2 × 109 1/mol; mean Cap = 17.4 × 10−15 mol/100 μg DNA) were found. The glucagon stimulated increase in plasma cyclic AMP was studied in 6 healthy subjects and the four members of the family. The plasma cyclic AMP levels of the patients with hormone resistance were generally within the normal range. These observations demonstrate that in these patients with peripheral resistance to thyroid hormone binding of T3 to the receptor in the nucleus of lymphocytes is normal; in relation to the high circulating thyroid hormone levels, the thyroid hormone mediated cyclic AMP response is disturbed, suggesting that the defect is at the post-receptor effector level.

scholarly journals SAT-434 Phenotype and Genotype Analysis of Patients with Resistance to Thyroid Hormone β: A Single-Center Experience

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Karn Wejaphikul ◽  
Prapai Dejkhamron ◽  
Stefan Groeneweg ◽  
W Edward Visser ◽  
Kevalee Unachak ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Mutation Analysis ◽  
Novel Mutation ◽  
Family Members ◽  
Antithyroid Drugs ◽  
Thyroid Function Tests ◽  
Resistance To Thyroid Hormone ◽  
The Mean ◽  
The Impact

Abstract Introduction Resistance to thyroid hormone β (RTHβ) is caused by mutations in THRB, the gene that encodes thyroid hormone receptor β. The clinical phenotype is variable and may include goiter, tachycardia, and learning disability with or without hyperactive behavior. The biochemical hallmark of RTHβ is elevated T4 and T3 with non-suppressed TSH concentrations. We here describe the phenotype and genotype of three Thai patients diagnosed with RTHβ in a pediatric referral center. Patients had previously been misdiagnosed and inappropriately treated with antithyroid drugs (ATDs). Methods Clinical features and thyroid function tests (TFTs) of three unrelated RTHβ patients were retrospectively reviewed. Genomic DNA of the RTHβ patients and affected family members was amplified for exon 7-10 of the THRB gene and sequenced to identify mutation by Sanger sequencing. The impact of the p.L341V novel mutation on the affinity for T3 and T3-induced transcriptional activity was previously determined in vitro. Results Three female patients were diagnosed with RTHβ. All of them had been misdiagnosed with hyperthyroidism and treated with ATDs prior to referral. The mean age at diagnosis was 8 years. The main presenting symptoms were diffuse goiter and tachycardia. The mean duration of ATD treatment was 3 years. During the treatment, patients had fluctuating thyroid hormone and increased TSH levels. An older sister and mother of one patient also had similar TFTs abnormalities, for which the mother had undergone a subtotal thyroidectomy. RTHβ was diagnosed based on the high FT3 and FT4 with normal (non-suppressed) TSH concentrations and confirmed by mutation analysis. Anti-thyroid peroxidase, anti-thyroglobulin, and TSH receptor antibody (TRAb) were negative, excluding autoimmune thyroid disease. Heterozygous missense mutations of the THRB gene were identified in all patients and affected family members. Two mutations had been previously reported (p.R243W and p.L456F), and one mutation was novel (p.L341V). In vitro studies confirmed an important role of Leu341 in T3 binding of the TRβ and functional impairment of the p.L341V novel mutation and were reported separately. According to available literature, only nine Thai RTHβ patients (in three families) carrying three different mutations (p.G251V, p.M313T, and p.A317T) had been previously reported. Goiter was the most common clinical finding, and almost all patients had a history of receiving unnecessary treatment with ATDs. Conclusion We report a series of RTHβ patients carrying THRB gene mutations, including one novel mutation (p.L341V). Clinicians should be alert that RTHβ can be found in patients with goiter and tachycardia. Elevated T4 and T3 with non-suppressed TSH concentration is the main diagnostic clue for this disease. Mutation analysis allows definitive diagnosis of RTHβ and may help to avoid potential misdiagnosis and improper treatment.

scholarly journals 418 PERIPHERAL RESISTANCE TO THYROID HORMONE IN AN INFANT

1981 ◽  
Vol 15 ◽  
pp. 509-509
Author(s):  
Paul B Kaplowitz ◽  
A Joseph D'Ercole ◽  
Robert D Utiger ◽  
Louis Underwood
Keyword(s):  
Thyroid Hormone ◽  
Peripheral Resistance ◽  
Resistance To Thyroid Hormone

Partial peripheral resistance to thyroid hormone

1981 ◽  
Vol 70 (5) ◽  
pp. 1115-1121 ◽  
Author(s):  
Michael M. Kaplan ◽  
Stephen L. Swartz ◽  
P.Reed Larsen
Keyword(s):  
Thyroid Hormone ◽  
Peripheral Resistance ◽  
Resistance To Thyroid Hormone

Changes in cytosolic 3,5,3′-tri-iodo-l-thyronine (T3) binding activity during administration of l-thyroxine to thyroidectomized rats: cytosolic T3-binding protein and its activator act as intracellular regulators for nuclear T3 binding

1989 ◽  
Vol 123 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Y. Nishii ◽  
K. Hashizume ◽  
K. Ichikawa ◽  
T. Miyamoto ◽  
S. Suzuki ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Nuclear Receptor ◽  
Binding Capacity ◽  
Binding Protein ◽  
Binding Activity ◽  
Affinity Constant ◽  
Maximal Binding

ABSTRACT Changes in the amount of cytosolic 3,5,3′-tri-iodo-l-thyronine (T3)-binding protein (CTBP) and its activator during administration of l-thyroxine (T4) to thyroidectomized rats were investigated. Thyroidectomy decreased the amount of CTBP in the kidney, whereas the activator was not significantly modified by thyroidectomy. The activator was increased by administration of T4 to thyroidectomized rats. The amount of CTBP was also increased by administration of T4. The activator increased the maximal binding capacity (MBC) without changes in the affinity constant for T3 binding in CTBP. A T4-induced increase in MBC in cytosol inhibited nuclear T3 binding in vitro by competition of T3 binding between CTBP and the nuclear receptor. These results suggest that thyroid hormone increases the capacity for cytosolic T3 binding through increasing the amount of CTBP and its activator, and that these increases play a role in regulating the amount of T3 that binds to its nuclear receptor. Journal of Endocrinology (1989) 123, 99–104

TRIIODOTHYRONINE AND THYROXINE NUCLEAR RECEPTORS IN LYMPHOCYTES FROM NORMAL, HYPER- AND HYPOTHYROID SUBJECTS

1977 ◽  
Vol 85 (1) ◽  
pp. 44-54 ◽  
Author(s):  
Th. Lemarchand-Béraud ◽  
A.-Ch. Holm ◽  
B. R. Scazziga
Keyword(s):  
Nuclear Receptors ◽  
Binding Sites ◽  
Intact Cell ◽  
Affinity Constant ◽  
Limited Capacity ◽  
Intact Cells ◽  
High Affinity ◽  
The Mean ◽  
Hypothyroid Patients ◽  
Hyperthyroid Patients

ABSTRACT In an investigation of thyroxine (T4) and triiodothyronine (T3) receptors in humans, the lymphocyte was chosen as the target cell. This study was performed to elucidate whether T3 and T4 bind to different receptors, if T4 is bound only after conversion into T3, and whether there is any modification of the receptors in hyper- and hypothyroidism. Lymphocytes were found to possess a high-affinity, limited-capacity binding sites for both T4 and T3. The mean equilibrium affinity constant (Ka) was 2.28 · 1010 ± 0.21 m−1 for T3, and 0.98 · 1010 ± 0.16 m−1 for T4. The mean number of saturable binding sites was 115 for T3, and 102 for T4. The binding capacities and affinities also determined in the lymphocyte nuclei isolated after incubation of the intact cell, were similar to those observed in the intact cells. In competition experiments, labelled T4 was as readily displaced by T3 as by T4 itself, whereas labelled T3 was displaced only by a 40 times higher concentration of T4 than T3. These observations suggest identical receptors for the two hormones and a binding of T4 as such, provided it is not in competition with T3. In lymphocytes from hyperthyroid patients, receptor affinities and numbers remained unchanged. In lymphocytes from hypothyroid patients, the affinity was normal, but the mean number of T3 binding sites was increased to 310 (P < 0.001), to return to normal after a few months of treatment.

THYROID HORMONE-BINDING INTERACTIONS IN CYTOSOL OF RAT ANTERIOR PITUITARY

1977 ◽  
Vol 85 (2) ◽  
pp. 256-266 ◽  
Author(s):  
Valerie Anne Galton
Keyword(s):  
Thyroid Hormone ◽  
Binding Sites ◽  
Anterior Pituitary ◽  
Binding Capacity ◽  
Relative Effectiveness ◽  
Binding Activity ◽  
Rat Tissues ◽  
Hormone Binding ◽  
Cytosol Fraction ◽  
Binding Interactions

ABSTRACT Thyroxine (T4) and triiodothyronine (T3)-binding interactions in preparations of rat anterior pituitary gland have been studied. T4 is bound primarily to extranuclear binding sites located in the cytosol fraction of the cell. These sites have a medium affinity for T4: Ka = 2.5 × 108 1/mol and a maximum binding capacity (MBC) of 1.15 pmol/mg tissue (wet weight). Binding of T3 to these sites is minimal. The extent of binding of T4 is influenced by the pH of the system and the temperature of incubation. The relative effectiveness of T4 analogues in displacing bound T4 is tetrac > T4 > triac > D-T4 > T3. Similar T4-binding sites are present in other rat tissues, but in all except serum, binding activity is lower than in the pituitary. T4-binding by serum contaminating the pituitary preparations contributed only partially to the total activity observed. Concomitant assessment of T4-binding activity and T4 metabolism in pituitary homogenates prepared at different pH values indicated an inverse relationship between the two processes. The possible role of thyroid hormone binding in cytosol in influencing the intracellular distribution of thyroid hormones is discussed.

scholarly journals Altered Intracellular Trafficking of Mutant Thyroid Hormone Receptors in Resistance to Thyroid Hormone Syndrome

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A973-A973
Author(s):  
Hannah P Tofil ◽  
Lizabeth Ann Allison
Keyword(s):  
Thyroid Hormone ◽  
Dna Binding ◽  
Nuclear Receptor ◽  
Binding Sites ◽  
Intracellular Trafficking ◽  
Binding Domain ◽  
Wild Type ◽  
Resistance To Thyroid Hormone ◽  
Helix 12 ◽  
The Impact

Abstract Resistance to Thyroid Hormone α (RTHα), a reduced sensitivity to thyroid hormone (T3) in peripheral tissues, is caused by mutations in thyroid hormone receptor α (TRα), a nuclear receptor that mediates T3-responsive gene expression. All mutations characterized in RTHα, to date, are in the ligand binding domain (LBD), resulting in reduced affinity for T3. In addition, some mutations result in truncated proteins lacking all or part of helix 12. Previously, we have used fluorescence recovery after photobleaching (FRAP) to examine the effects of select RTHα mutations on the intracellular trafficking of TRα. After transfecting HeLa cells with expression plasmids for green fluorescent protein (GFP)-tagged wild-type TRα and each of the mutants, we first assessed their intracellular distribution and initial intranuclear mobility. Although wild-type TRα is known to shuttle between the nucleus and cytoplasm, it is primarily localized to the nucleus at a steady state. We showed that TR-E403X, Ala382ProfsX7, and F397fs406X are also primarily localized to the nucleus, and FRAP revealed that wild-type TRα and the RTHα mutants are highly dynamic within the nucleus, indicating that the receptors rapidly dissociate and reassociate with DNA binding sites and/or other nuclear binding sites, independent of T3 (1). Some studies have shown that Nuclear Receptor Corepressor 1 (NCoR1), which interacts with the hinge region of TRα (the region between the DNA-binding domain and LBD) has a higher affinity for RTHα mutants compared to wild-type TRα, supporting the hypothesis that helix 12 of the LBD also functions to disassociate NCoR1 from TRα when it is bound to T3 (2). We proposed that this increased affinity for NCoR1 alters the mobility of TRα in the nucleus, impacting its function. Here, we show that NCoR1 has slower FRAP recovery kinetics compared with TRα, and we evaluate the intranuclear dynamics of RTH TRα1 mutants ΤR-E403X, Ala382ProfsX7, and F397fs406X in response to increased levels of NCoR1. Investigation of the effects of overexpression of NCoR1 will provide further insight into the impact of altered binding affinity for NCoR1 on the intranuclear dynamics of RTHα mutants. References: (1) Femia et al., Journal of Cellular Biochemistry, 2020 2020 Apr; 121(4), 2909-2926.(2) Bochukova et al., New England Journal of Medicine, 2012 Jan. 19; 366(3), 243–249.

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