Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The thyroid hormones thyroxine (T4) and 3,3',5-L-triiodothyronine (T3) stimulate plasma membrane Ca2+-ATPase (EC 3.6.1.3) activity in human erythrocytes by a mechanism independent of the cell nucleus. The current studies were conducted to determine the effect of retinoic acid on the extranuclear activation by T4 and T3 of Ca2+-ATPase in the human red cell. The retinoid inhibited basal and T4-stimulatable activity of that enzyme in a dose-dependent manner. At the highest tested concentration (10(-6) M), retinoic acid inhibited basal enzyme activity by 25% and T4-stimulated activity by 72%. A concentration as low as 5 x 10(-10) M retinoic acid shifted the dose-response curve of both T4 and T3 so that the concentration of each associated with maximal enzyme stimulation was 10(-9) M instead of 10(-10) M. Retinoic acid displaced [125I]T4 binding to red cell membranes as effectively as unlabeled T4. Retinol failed to influence either basal or T4-stimulated enzyme activity or to displace T4 binding. These results indicate that retinoic acid can partially block the T4 and T3 stimulation of Ca2+-ATPase in human red cell membranes and suggest a physiologic role for the retinoid as a modulator of this peripheral action of thyroid hormone. They suggest that the red cell membrane is an important site of action for this active retinoid.
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PMID:Retinoic acid is a modulator of thyroid hormone activation of Ca2+-ATPase in the human erythrocyte membrane. 252 37

The Ca2(+)-ATPase of plasma membranes from a variety of tissues is subject to stimulation in vitro, and apparently in vivo, by physiological concentrations of iodothyronines regarded as biologically active in other bioassay systems. This calmodulin-dependent action of thyroid hormone is nongenomic, that is, directly on the cell membrane and independent of the cell nucleus. In the case of human erythrocyte Ca2(+)-ATPase, this assay of thyroid hormone bioactivity is attractive as an in vitro, readily-studied model of hormone action in a human cell. Enzyme activity is paralleled, as expected, by changes in calcium pump activity. Thyroid hormone action in this system is subject to modulation by glucose and by a variety of compounds which, like iodothyronines, are hydrophobic. The mechanism of thyroid hormone action on membrane Ca2(+)-ATPase involves, at least in part, membrane lipids, including components of the phosphatidylinositol cycle. The physiologic role of thyroid hormone action on cell membrane Ca2(+)-ATPase is speculative. In plasma membranes of nonexcitable and excitable tissues, ambient thyroid hormone may set basal activity of Ca2(+)-ATPase or magnitude of the enzymatic response to calmodulin Ca2+.
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PMID:Thyroid hormone regulation of membrane Ca2(+)-ATPase activity. 253 10

On the basis of rat model of congenital hypothyroidism, the following problems were investigated: (1) The biochemical changes of DNA amount in cerebrum, and increase of DNA concentration & decline of protein/DNA in cerebellum. (2) The mitochondria ATPase activity of the cells in cerebral cortex was significantly diminished in hypothyroidism, suggesting that energy metabolism of brain was affected by thyroid hormone. (3) The serum T4 level of hypothyroid offsprings was markedly decreased with increase of serum TSH concentration, while the serum T3 content showed no change. However, 131I uptake rate of thyroid was elevated with peak ahead of time in hypothyroid rats. (4) All the hypothyroid rats were accompanied with delayed body weight growth and decreased weight of brain and several other organs. (5) After replacement therapy with thyroid all the indices mentioned above were improved.
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PMID:[Influence of congenital hypothyroidism on the developing rat brain and improvement after thyroid replacement therapy]. 253 92

We have shown previously that in the ferret heart there are two isoforms of Na+-K+-ATPase, alpha(+) and alpha, and that these isoforms undergo developmental changes. In the present study, we examine regulation of the isoenzymes by thyroid hormone, which is well known to increase activity of Na+-K+-ATPase in different tissue preparations. Ferrets were injected with L-thyroxine (T4) (0.5 mg/kg, sc) for 3 wk. The T4-treated ferrets gained 58 +/- 32 g body wt compared with 366 +/- 24 g for the control ferrets. Plasma 3,5,3'-triiodothyronine concentrations of the T4-treated animals increased about eightfold 16-18 h after the last injection. The number of alpha(+)- and alpha-subunits in heart homogenates estimated by [3H]ouabain binding was 3.5 +/- 0.1 and 2.5 +/- 0.1 pmol/mg protein, respectively [alpha(+)/alpha = 1.40]. In the T4-treated ferrets, there was no significant increase of the alpha(+)-isoform (3.2 +/- 0.2 pmol/mg protein), whereas the number of alpha-isoform increased significantly to 4.1 +/- 0.3 pmol/mg protein [alpha(+)/alpha = 0.78]. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of partially purified cardiac plasma membrane preparations reveals similar pattern of changes of the isoenzymes. In the kidney, however, there was no significant change in the number of alpha-isoform, which is the predominant isoform in the kidney, and T4 does not appear to induce synthesis of alpha(+)-isoform in the kidney. It is concluded that thyroid hormone induces both isoform- and tissue-specific regulation of the Na+-K+-ATPase alpha-subunits in the ferret. These specific regulations of the isoforms seem to suggest important physiological roles of the isoenzymes.
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PMID:Tissue-specific isoform regulation of Na+-K+-ATPase by thyroid hormone in ferrets. 254 5

We investigated interactions between noradrenaline and thyroid hormone status in the regulation of (Na+,K+)-ATPase in vivo. Treatment with the beta-adrenoceptor antagonist propranolol or with the neurotoxin 6-hydroxydopamine did not prevent the increases in heart (Na+,K+)-ATPase associated with triiodothyronine treatment. Administration of methimazole did not prevent the increase in (Na+,K+)-ATPase indices in cerebral cortex and heart associated with subacute noradrenergic stimulation by yohimbine. There was no evidence for synergistic effects between thyroid hormone administration and noradrenergic stimulation by yohimbine. Thyroid hormone, unlike noradrenaline, mainly increased (Na+,K+)-ATPase activity with low affinity for ouabain. These results show that noradrenaline and thyroid hormone regulate (Na+,K+)-ATPase by largely independent mechanisms, and may regulate different populations of enzyme molecules.
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PMID:Noradrenaline and thyroid function regulate (Na+,K+)-adenosine triphosphatase independently in vivo. 255 49

Gentamicin nephrotoxicity increases renal cortex calcium and sodium and decreases renal cortex Na-K-ATPase activity. Human acute renal failure is accompanied by an increase in parathyroid hormone (PTH), a hormone that stimulates calcium uptake by tissues, and by a decrease in thyroid hormone, a hormone that increases renal cortex Na-K-ATPase activity. This study evaluated the role of extracellular calcium, PTH, and thyroxine in the pathogenesis of gentamicin nephrotoxicity. Chronically parathyroidectomized hypocalcemic rats (PTXG) given gentamicin (30 mg/kg s.c. twice daily for 8 days) were not protected from renal failure when compared with intact rats given gentamicin (NG), serum creatinine being 4.4 +/- 1.0 and 3.7 +/- 0.7 mg/dl, respectively, compared with normals (N), 1.2 +/- 0.1 mg/dl. Rats given thyroxine (10 micrograms/100 g body wt for 10 days) before and during gentamicin (PTXT4G) had a serum creatinine not significantly different from normals, 2.1 +/- 0.4 mg/dl. Plasma T4 was reduced in PTXG, NG, and PTXT4G compared with N, but the value for PTXT4G was significantly higher than for either PTXG or NG. Renal cortex Na-K-ATPase activity (mumol Pi X mg prot-1 X h-1) was lower in PTXG (2.3 +/- 0.2) and NG (2.4 +/- 0.5) compared with N (3.7 +/- 0.1), but activity was not reduced in PTXT4G (3.2 +/- 0.2) Thyroxine was protective also against gentamicin nephrotoxicity in intact rats. Clearance and excretion studies indicated that this protection did not result from an increase in glomerular filtration rate, filtered load of calcium, or urinary calcium excretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Protective effect of thyroxine but not parathyroidectomy on gentamicin nephrotoxicity. 257 82

Recently a number of possible functions for ergothioneine (ERT) have been suggested (1). This paper elaborates on some of these in light of overlooked or recent publications and presents additional hypotheses including: 1. Reduced ERT (ergothionol) may be an acyl carrier. 2. ERT, in conjunction with thyroid hormone and iodine, may be a cofactor in peroxidative and oxidative reactions. 3. ERT and thyroid hormone may be required for the oxidation of reduced pyridine nucleotides and the coupling of this to oxygen consumption (respiration) and ATP generation/ATPase action (heat production). 4. ERT may be required for both gene expression and repair. 5. 2-Thioimidazoles (ERT and 2-thiourocanic acid in particular) may be immunoregulatory. 6. ERT may be involved in the protection from oxidation (inactivation) of methionine and methionine containing chemoattractants, hormones, tRNA, etc. Some future research activities are suggested.
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PMID:In search of a physiological function for L-ergothioneine--II. 267 18

The effects of thyroid hormone on nuclear-encoded mitochondrial inner membrane proteins were investigated by in vitro translation of the endogenous mRNA present in a postmitochondrial fraction from the livers of rats treated in vivo with hormone. The levels of the mRNAs were estimated by quantitative immunoabsorption of the translation mixture. Total protein synthesis was increased 2.6-fold after 4 days of in vivo hormone treatment, but only 10-15% of the polypeptides were dramatically altered (greater than 5-fold). Among the most highly elevated were cytochrome c1 (greater than 10-fold increase) and the Rieske iron-sulfur protein of the cytochrome bc1 complex. Other inner membrane proteins (core protein 1, beta subunit of F1 ATPase, subunit IV of cytochrome oxidase, 3-hydroxybutyrate dehydrogenase) and non-mitochondrial proteins (rat serum albumin, beta 2-microglobulin) were not altered significantly by hormone treatment. Cytochrome c1 and the Rieske protein increased after 12 h of hormone treatment, a relatively early response in mammalian mitochondrial biogenesis. The possible significance of this response for the regulation of mitochondrial synthesis and assembly is discussed.
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PMID:Thyroid hormone regulation of nuclear-encoded mitochondrial inner membrane polypeptides of the liver. 277 68

Whether Na+ movement through the plasma membrane plays a role in thyroid hormone uptake was investigated in intact rat soleus muscles. After preincubation for 120 min at 37 degrees C in modified Krebs-Ringer bicarbonate containing 140 or 5 mM Na+ plus choline or lithium to maintain osmolarity, muscles were incubated with 50 pM [125I]triiodo-L-thyronine (T3) or [125I]L-thyroxine (T4) for 60 min. T3 uptake was decreased when extracellular Na+ was replaced by either choline or lithium, the amount of decrease corresponding to the specific (or saturable) uptake component. Monensin, an ionophore that stimulates Na+ entry, increased T3 uptake at 140 mM Na+ but not at 5 mM Na+. Amiloride, a Na+/H+ exchange inhibitor, had no effect on T3 uptake under basal conditions or when Na+ was replaced by choline, but reversed the action of lithium. Ouabain, an inhibitor of Na+/K+ ATPase, reduced specific T3 uptake. T4 uptake was unaffected by low extracellular Na+. These results are consistent with a major role of Na+ movement in T3 uptake by skeletal muscle, but not in T4 uptake, and suggest an involvement of membrane pumps in this process.
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PMID:Role of sodium in thyroid hormone uptake by rat skeletal muscle. 282 Oct 72

We have analyzed the relationship between expression of the transformed phenotype and thyroid hormone (triiodothyronine, T3) inducibility of Na,K-ATPase and binding of 125I-epidermal growth factor (EGF) to cell membrane receptors in wild-type (wt) and mutant type 5 adenovirus (Ad5)-transformed CREF cells displaying a cold-sensitive (cs) expression of the transformed phenotype. CREF cells respond to thyroid hormone treatment with increased Na,K-ATPase activity and bind similar levels of 125I-EGF at 32 degrees C, 37 degrees C and 39.5 degrees C. In contrast, CREF cells transformed by wt Ad5 or the E1a plus E1b-transforming genes of wt Ad5 are refractile to T3 treatment and bind lower levels of 125I-EGF than CREF cells at all three temperatures. By employing a series of cloned CREF cell lines transformed by a host-range cold-sensitive mutant virus, H5hr1 or H5dl101, or the E1a or E1a plus E1b genes from these viruses, we have investigated expression of the transformed state and its relationship with hormone inducibility and EGF binding. When cs virus, cs E1a- or cs E1a plus E1b-transformed CREF clones were grown at 32 degrees C, a nonpermissive transforming temperature in which cs-transformed cells exhibit properties similar to untransformed CREF cells, T3 induced Na,K-ATPase activity and these cells bound similar levels of 125I-EGF as CREF cells. However, when cs virus- and cs Ela plus E1b-transformed CREF clones were incubated at 37 degrees C or 39.5 degrees C, temperatures at which cs-transformed cells exhibit properties similar to wt Ad5-transformed CREF cells, they did not respond to T3 and bound lower levels of 125I-EGF than CREF cells. In the case of cs E1a-transformed CREF clones, thyroid hormone responsiveness was observed at both 32 degrees C and 37 degrees C, but not at 39.5 degrees C. By performing temperature shift experiments--i.e. 32 degrees C to 37 degrees C, 32 degrees C to 39.5 degrees C, 37 degrees C to 32 degrees C, and 39.5 degrees C to 32 degrees C, it was demonstrated that after a shift from lower to higher temperature a 24-hr lag period was required for cs-transformed CREF cells to lose T3 inducibility and exhibit reduced EGF binding, whereas 96 hr after a shift from higher to lower temperature a 96-hr lag period was required for cs-transformed cells to regain T3 inducibility and increased 125I-EGF binding.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Regulation of thyroidal inducibility of Na,K-ATPase and binding of epidermal growth factor in wild-type and cold-sensitive E1a mutant type 5 adenovirus-transformed CREF cells. 282 99


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