Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The interaction between thyroid hormone (T3) and nutritional signals has been of interest for nearly a century. Thus, enhanced glucose production, absorption and utilization are associated with hyperthyroidism, whereas diminished glucose utilization and lipogenesis characterize hypothyroidism. Recent studies have uncovered what appears to be yet another area of interaction at the molecular level. On the one hand, a marked overlap exists between the changes in rat hepatic mRNA activity profile induced by hyperthyroidism and high carbohydrate administration. On the other hand, the patterns produced by hypothyroidism, starvation and diabetes are characterized by oppositely directed shifts. These findings may be due, in part, to a synergistic relationship between carbohydrate feeding and T3 administration in the induction of many hepatic lipogenic enzymes and their respective mRNAs. Studies both in the intact rat as well as in isolated hepatocyte cultures indicate that this synergism arises from the ability of T3 to multiply an intracellular signal derived from the metabolism of glucose. The development of recombinant DNA techniques can now be applied to the study of the interaction of T3 with nutritional signals. Initial efforts have demonstrated a hepatic mRNA (mRNAS14) rapidly responsive to both T3 and carbohydrates. With this probe, studies are under way to define the precise molecular mechanisms by which T3 and carbohydrates interact to influence gene expression.
Mol Cell Endocrinol 1985 Nov
PMID:Interaction of thyroid hormone and nutritional signals on thyroid hormone action. 299 7

The effects of propylthiouracil (PTU) treatment on vasopressin, angiotensin II, glucagon and alpha 1-adrenergic receptors in both developing and adult rats were studied in liver membrane preparations by measuring the binding of the following ligands: [3H][8-lysine]vasopressin, [3H]Sar-angiotensin II, [125I]glucagon and [3H]prazosin, and in the case of glucagon, by measuring adenylate cyclase activation. Whatever the ligand used, in young as well as in adult animals, PTU treatment led to a similar reduction (about 50%) in the maximal number of binding sites (Bmax), without significant changes in the apparent dissociation constant (KD) of labeled hormone for its specific receptor. In normal adult animals, thyroxine treatment, i.e. hyperthyroidism, had an opposite effect on the Bmax (25-50% increase), without changes in the KD. In developing PTU-treated rats, the abnormalities completely disappeared after therapy with increasing physiological doses of thyroxine; consequently they were directly related to thyroid deficiency and not to toxic effects of PTU. Moreover, the abnormalities resulting from induced hypothyroidism were reversible. In developing and adult hypothyroid rats, neither basal, NaF-, nor Gpp(NH)p-stimulated adenylate cyclase activities were significantly affected. Glucagon-sensitive adenylate cyclase activity seemed to be slightly increased (by about 15%), without changes in the apparent activation constant (Kact). These results are considered in parallel with findings on plasmatic glucagon and vasopressin levels, compared with similar previous reports related to renal vasopressin receptors, and discussed with respect to unpublished observations concerning hepatic responsiveness to glycogenolytic hormones in young and adult rats with induced hypothyroidism.
Mol Cell Endocrinol 1987 May
PMID:Comparative study of the developmental patterns of vasopressin, glucagon, angiotensin II, and alpha 1-adrenergic receptors in the liver of developing and adult hypothyroid rats. 303 20

In a previous study we were able to separate, using cluster analysis, 196 patients with Graves' disease evaluated for a large number of clinical and laboratory characteristics, including HLA-A and HLA-B typing into one subset with recurring disease and a high prevalence of ophthalmopathy and another subset with mild disease and little ophthalmopathy. Prevalence of HLA-B8 was much higher in the first as compared to the second group. The present study was undertaken in 117 new patients with Graves' disease, typed for HLA-A, HLA-B, HLA-C and DR antigens and IgG heavy chain markers, to determine whether these characteristics could be used to segregate patients into clinically relevant subsets. There was a greater proportion of Gm fb homozygotes among patients than among controls (chi2 = 4.71, p less than 0.05) as well as individuals with HLA-B8 and DR3, previously documented for this disease. Two patient clusters were identified. In one (C1), there is a high incidence of exophthalmos, recurrence of hyperthyroidism after drug treatment, high titres of anti-thyroglobulin antibody, and an association with other autoimmune (including thyroid) diseases, a tendency for the disease to be familial and the presence of larger goitres. The incidence of HLA-B8 was greater in C1, while HLA-B12 was more frequent in the mild cluster, C2. HLA-DR3 was found to be associated with patients in the severe cluster and HLA-DR2 with patients in the mild cluster.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Biol Med 1986 Feb
PMID:Heterogeneity by cluster analysis techniques of Graves' patients typed for HLA DR and IgG heavy chain markers. 308 92

Triiodothyronine added at 0.1 nM to 3T3-F442A cells cultured in adipogenic medium having endogenous hormone concentrations similar to those of hypothyroid serum stimulated adipose conversion; activities of both lipogenic enzymes, glycerophosphate dehydrogenase and malic enzyme, increased with hormone treatment. The number of adipocytes was also augmented by L-T3 addition but the number of fat cell clusters remained the same as compared to non-treated cultures, suggesting that thyroid hormone increased the number of adipocytes probably through stimulating selective multiplication of precursor adipose cells. Hormone addition to cells cultured with non-adipogenic medium did not promote conversion showing that L-T3 is not an adipogenic factor by itself. Triiodothyronine added at concentrations similar to those found in hyperthyroidism, from 10 nM up to 10 microM, also increased the proportion of adipocytes without changing the number of fat cell clusters, but they decreased the activity of both lipogenic enzymes and lipid accumulation in mature adipocytes. It can be concluded that during 3T3-F442A differentiation into adipocytes L-T3 increases the number of differentiated adipocytes and, at low concentrations, also enhances lipogenic enzyme activities, whereas at the hyperthyroid hormone levels these enzyme activities are significantly reduced, remaining at levels similar to those of cells cultured with hypothyroid medium. This cloned cell line seems to be a useful model to study thyroid hormone action at both molecular and cellular level.
Mol Cell Biochem 1987 Jul
PMID:Thyroid hormone stimulates adipocyte differentiation of 3T3 cells. 362 13

Employing a specific radioimmunoassay for quantification, the kinetics of estrogen-induced elevation in the plasma concentration of biotin-binding protein (BBP) in immature male chicks was investigated. A single injection of the steroid hormone enhanced the plasma BBP content several-fold at 6 h, reaching peak levels around 48 h and declining thereafter. A 2-fold amplification of the response was evident during secondary stimulation with the hormone. The magnitude of the response was hormonal dose-dependent while the initial lag phase and the time of peak protein accumulation were unaltered within the hormonal doses tested. The circulatory half-life of the specific protein in normal and estrogenized birds was 10 h. Hyperthyroidism markedly decreased the hormonal response while the opposite effect was seen during hypothyroidism. The antiestrogens E- and Z-clomiphene citrate effectively blocked the protein induction whereas progesterone, either alone or in combination with estrogen, was ineffective in modulating the induction. Cycloheximide administration drastically inhibited the inductive response. The above observations clearly suggest that the genes corresponding to the two isofunctional proteins of chicken egg, viz. BBP and avidin, are differentially regulated.
Mol Cell Endocrinol 1985 Apr
PMID:Estrogen induction of biotin-binding protein in immature chicks: kinetics, hormonal specificity and modulation. 399 48

Hyperthyroidism induces a number of metabolic and physiological changes in the heart including hypertrophy, increase in inotropic status, and alterations of myocardial energy metabolism. The effects of hyperthyroidism on adenosine metabolism which is intimately involved in the control of many aspects of myocardial energetics, have not been clarified. The aim of this study was thus to evaluate the potential role of adenosine in the altered physiology of the hyperthyroid heart. Transport of adenosine was studied in cardiomyocytes isolated from hyperthyroid and euthyroid rats. Activities of different enzymes of purine metabolism were studied in heart homogenates and concentrations of nucleotide and creatine metabolites were determined in hearts freeze-clamped in situ. Both transport of adenosine into cardiomyocytes and the rate of intracellular phosphorylation were higher in the hyperthyroid rat. At 10 microM concentration, adenosine transport rates were 275 and 197 pmol/min/mg protein in hyperthyroid and euthyroid cardiomyocytes respectively whilst rates of adenosine phosphorylation were 250 and 180 pmol/min/mg prot. An even more pronounced difference was observed if values were expressed per number of cells due to cardiomyocyte enlargement. Hyperthyroidism was associated with a 20% increase in adenosine kinase, 30% decrease in membrane 5'-nucleotidase and 15% decrease in adenosine deaminase activities measured in heart homogenates. In addition there was a substantial depletion in the total creatine pool from 63.7 to 41.6 mumol/g dry wt, a small decrease in the adenylate pool (from 27.2 to 24.3 mumol/g dry wt) and an elevation of the guanylate pool (from 1.22 to 1.36). These results show that adenosine transport and phosphorylation capacity is enhanced in hyperthyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Biochem 1995 Feb 23
PMID:Hyperthyroidism increases adenosine transport and metabolism in the rat heart. 759 49

Hyperthyroidism [produced by the administration of 3,5,3'-triiodothyronine (T3) for 3 days to adult rats] increased PDH kinase activities of freshly isolated cardiomyocytes by 1.6-fold. The effects of hyperthyroidism and 48 h-starvation to increase PDH kinase activities were additive. Culture of cardiomyocytes prepared from fed, euthyroid rats for 25 h with T3 (100 nM) increased PDH kinase activities to values comparable in magnitude to those observed in response to experimental hyperthyroidism in vivo. PDH kinase activities in cardiomyocytes from fed, euthyroid rats after culture with n-octanoate (1 mM) or dibutyryl cyclic AMP (DBcAMP)(50 microM) exceeded those of freshly isolated myocytes. DBcAMP and T3 were without further effect in the presence of n-octanoate. The inclusion of insulin (100 microU/ml) alone in the culture medium did not affect PDH kinase activity, but insulin suppressed the effects of T3, DBcAMP and n-octanoate to increase cardiomyocyte PDH kinase activity in culture. PDH kinase activities in cardiomyocytes isolated from starved rats declined after 25 h of culture. This decline was prevented by the inclusion of T3, but not of DBcAMP, in the culture medium. Insulin (100 microU/ml) suppressed the effects of T3 to oppose the loss of cardiomyocyte PDH kinase activity experienced during culture. The results demonstrate that hyperthyroidism leads to a stable increase in the activity of cardiomyocyte PDH kinase, a response that is mimicked by T3 in vitro. Insulin opposes the effects of T3 (and of fatty acids and cyclic AMP) to increase PDH kinase activity in cultured cardiomyocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
J Mol Cell Cardiol 1995 Mar
PMID:Interactive effects of insulin and triiodothyronine on pyruvate dehydrogenase kinase activity in cardiac myocytes. 760 8

The effect of triiodothyronine (T3) on regulation of fatty acid synthase in chicken liver was investigated. In hypothyroid animals, enzyme activity was about one half of that in euthyroid animals. T3 treatment increased the enzyme activity in hypothyroid animals. There is little difference in both the mRNA concentration and the transcription rate between euthyroid and hypothyroid animals. T3 treatment markedly decreased both the mRNA concentration and the transcription rate in euthyroid and hypothyroid animals. These results suggested that T3 maintained the normal level of enzyme expression primarily by stimulating the post-transcriptional step, while the transcription of the gene was inhibited by hyperthyroidism.
Mol Cell Biochem 1995 Mar 23
PMID:Thyroid hormone inhibits fatty acid synthase gene transcription in chicken liver. 762 81

Lipoprotein(a) [Lp(a)] is a low-density lipoprotein (LDL) particle in which apolipoprotein B-100 (apoB) is attached to a glycoprotein called apolipoprotein(a) [apo(a)]. Apo(a) has several genetically determined phenotypes differing in molecular weight, to which Lp(a) concentrations in plasma are inversely correlated. High plasma levels of Lp(a) are associated with atherosclerotic diseases. It is therefore of interest to study whether factors other than the apo(a) gene locus are involved in the regulation of Lp(a) concentrations. We measured plasma concentrations of Lp(a) and other lipoproteins and determined apo(a) phenotypes in 31 patients with hyperthyroidism, before and after the patients had become euthyroid by treatment. The mean concentration of LDL cholesterol rose from 2.67 to 3.88 mmol/l (P < 0.01), apoB rose from 0.79 to 1.03 g/l (P < 0.01), and the median Lp(a) concentration increased from 9.74 to 18.97 mg/dl (P < 0.01) on treatment. Lp(a) concentrations were inversely associated to the size of the apo(a) molecule both before (P < 0.01) and after treatment (P < 0.01). The increase in Lp(a) was significant in patients with high molecular weight apo(a) phenotypes (n = 9; P < 0.01) and in patients with low molecular weight apo(a) phenotypes (n = 16; P < 0.01), but not in those with apo(a) "null types" (n = 6; P = 0.5). The low levels LDL cholesterol and apoB in untreated hyperthyroidism may result from increased LDL receptor activity. The increase in Lp(a) levels were not correlated with the increase in LDL cholesterol or apoB.(ABSTRACT TRUNCATED AT 250 WORDS)
J Mol Med (Berl) 1995 Jan
PMID:Apolipoprotein(a) phenotypes and lipoprotein(a) concentrations in patients with hyperthyroidism. 763 41

We have previously shown that triiodothyronine (T3) regulates rat fatty acid synthesis in a tissue specific manner. Here, we determined the effects of thyroid state on mRNAs encoding the lipogenic enzymes, acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS). S14 mRNA, a sequence tightly associated with lipogenesis, was also measured. Levels of the three mRNA were 9-13-fold higher in hyper- than hypothyroid liver. Limited expression in kidney and heart was also increased by thyroid hormone. In brown adipose tissue, highest levels were recorded in hypothyroid animals. Thyroid state did not affect expression in lung and brain. All these changes are consistent with those previously measured in fatty acid synthesis. In white adipose tissue, mRNA expression was increased by hyperthyroidism. This increase may not be reflected in fatty acid synthesis, since we recently showed lipogenesis to be reduced under these circumstances. All three mRNAs responded rapidly to T3 in liver, but more slowly in kidney and fat. Thus, T3 regulates lipogenesis by altering levels of ACC and FAS mRNAs. S14 mRNA changes in parallel.
Mol Cell Endocrinol 1995 Apr 28
PMID:Tissue-specific regulation of lipogenic mRNAs by thyroid hormone. 767 39


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