The Ca2+- and reduced nicotinamide adenine dinucleotide phosphate- dependent hydrogen peroxide generating system is induced by thyrotropin in porcine thyroid cells

Carvalho, Denise Pires de

doi:10.1210/en.137.3.1007

Cited by 17 publications

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“…These data are in good agreement with those of Raspé and Dumont (10), who reported that TSH induces H 2 O 2 generator activity in dog thyrocytes by activating the adenylate cyclase cascade. They also corroborate our results showing that the TSH and/or forskolin stimulate NADPH oxidase activity in pig thyrocytes (11), which seems to be correlated with a higher expression of the flavoprotein (16).…”

Section: Tissue Distribution Of the P138supporting

confidence: 91%

Purification of a Novel Flavoprotein Involved in the Thyroid NADPH Oxidase

Dupuy¹,

Ohayon²,

Valent³

et al. 1999

Journal of Biological Chemistry

424

324

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Section: Tissue Distribution Of the P138supporting

confidence: 91%

Purification of a Novel Flavoprotein Involved in the Thyroid NADPH Oxidase

Dupuy¹,

Ohayon²,

Valent³

et al. 1999

Journal of Biological Chemistry

424

324

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“…As shown by Carvalho et al [20], the NADPH-dependent H,O, system is induced by thyrotropin. The present results show that the NADPH-K,Fe(CN), reductase in thyroid cells is also increased by chronic thyrotropin treatment, which provides further evidence that the NADPH-K,Fe(CN), reductase activity is associated with the H&generating system.…”

mentioning

confidence: 79%

Solubilization and Characterization of a Thyroid Ca²⁺‐Dependent and NADPH‐Dependent K₃Fe(CN)₆ Reductase

Gorin

Ohayon

Carvalho

et al. 1996

European Journal of Biochemistry

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The thyroid plasma membrane contains a Ca"-regulated NADPH-dependent H,O,-generating system which provides H,O, for the thyroid-peroxidase-catalyzed biosynthesis of thyroid hormones. The molecular nature of the membrane-associated electron transport chain that generates H,O, in the thyroid is unknown, but recent observations indicate that a flavoprotein containing a FAD prosthetic group is involved. Solubilization was reinvestigated using 3-[(3-cholamidopropyl)dimethylammonio]-l -propanesulfonate (Chaps), Triton X-100, and high salt concentrations. Chaps eliminated about 30% of the proteins, which included a ferricyanide reductase, without affecting the H,O,-generating system. Similarly, Triton X-100 alone did not extract the NADPH oxidase. An NADPH-oxidase activity, which was measured in the presence of the artificial electron acceptor potassium ferricyanide, was solubilized by increasing the ionic strength to 2 M KCI. This NADPH-ferricyanide reductase activity was shown to belong to the H,O,-generating system, although it did not produce H,O,. It was still Ca*+ dependent and H,O, production was restored by decreasing the ionic strength by overnight dialysis. No H,O, production activity was detected after sucrose density gradient centrifugation of the dialyzed solubilized enzyme, but a welldefined peak of NADPH oxidation activity with a sedimentation coefficient of 3.71 S was found in the presence of K,Fe(CN),. These results suggest that some unknown component(s) (phospholipid or protein) is removed during sucrose density gradient centrifugation. Finally, thyrotropin, which induces NADPH oxidase and regulates H,O, production in porcine thyrocytes in primary culture, also induced the NADPH-K,Fe(CN), reductase activity associated with the H,O,-generating system. Thus, this enzyme seems to be another marker of thyroid differentiation.

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“…These findings suggest that IOP releases iodide in vivo, since iodide appears to be a potent inhibitor of this enzymatic system both in vitro (11, 29) and in vivo (10). NADPH oxidase synthesis is dependent on the cAMP cascade stimulated by TSH in thyrocytes (30,31). Excess of iodide decreases cAMP in thyroid cells in response to TSH, but the strong inhibitory effect of iodide on thyroid NADPH oxidase, which was only found in the P 3000 g fraction of TDG, is probably not only due to decreased enzyme synthesis, as enzyme activity was within the normal range in the P 100 000 g from the same samples.…”

Section: Discussionmentioning

confidence: 81%

Effect of iodine or iopanoic acid on thyroid Ca2+/NADPH-dependent H2O2-generating activity and thyroperoxidase in toxic diffuse goiters

Cardoso

Martins

Campos

et al. 2002

European Journal of Endocrinology

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Objective: The aim of the present study was to compare the effects of iopanoic acid (IOP) or a saturated solution of potassium iodide (SSKI) administration to patients with toxic diffuse goiters (TDG). Design: Patients with TDG are treated with thionamides and high doses of iodine preoperatively. In this study, two types of preoperative drug regimens were used: propylthiouracil or methimazole plus SSKI for 10 -15 days ðn ¼ 8Þ or IOP for 7 days ðn ¼ 6Þ: Methods: Serum thyroid hormones (total and free thyroxine (T 4 ), total tri-iodothyronine (T 3 ) and reverse T 3 (rT 3 ), were evaluated after 7 days of either SSKI or IOP treatment, and after 10 -15 days of SSKI administration. During thyroidectomy, samples of thyroid gland were obtained to evaluate thyroperoxidase and thyroid H 2 O 2 -generating activities. Results: Serum total T 3 was significantly decreased after 7 days of either treatment, and serum rT 3 was significantly increased in IOP-treated patients. Serum total and free T 4 were unaffected by 7 days of IOP treatment, but decreased after 7 days of SSKI treatment, although significantly diminished levels were only reached after a further 3-8 days of SSKI administration. During both drug regimens, serum TSH remained low (SSKI: 0:159^0:122; IOP: 0:400^0:109 mU=ml). Thyroperoxidase activity was significantly lower in thyroid samples from patients treated with SSKI for 10-15 days than in the thyroid glands from IOP-treated patients. However, thyroid H 2 O 2 generation was inhibited in samples from patients treated with either IOP or SSKI. Conclusions: We show herein that IOP treatment can be effective in the management of hyperthyroidism and that this drug inhibits thyroid NADPH oxidase activity, just as previously described for SSKI, probably due to its iodine content.

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The Ca2+- and reduced nicotinamide adenine dinucleotide phosphate- dependent hydrogen peroxide generating system is induced by thyrotropin in porcine thyroid cells

Cited by 17 publications

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Purification of a Novel Flavoprotein Involved in the Thyroid NADPH Oxidase

Purification of a Novel Flavoprotein Involved in the Thyroid NADPH Oxidase

Solubilization and Characterization of a Thyroid Ca²⁺‐Dependent and NADPH‐Dependent K₃Fe(CN)₆ Reductase

Effect of iodine or iopanoic acid on thyroid Ca2+/NADPH-dependent H2O2-generating activity and thyroperoxidase in toxic diffuse goiters

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The Ca2+- and reduced nicotinamide adenine dinucleotide phosphate- dependent hydrogen peroxide generating system is induced by thyrotropin in porcine thyroid cells

Cited by 17 publications

References 0 publications

Purification of a Novel Flavoprotein Involved in the Thyroid NADPH Oxidase

Purification of a Novel Flavoprotein Involved in the Thyroid NADPH Oxidase

Solubilization and Characterization of a Thyroid Ca2+‐Dependent and NADPH‐Dependent K3Fe(CN)6 Reductase

Effect of iodine or iopanoic acid on thyroid Ca2+/NADPH-dependent H2O2-generating activity and thyroperoxidase in toxic diffuse goiters

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Solubilization and Characterization of a Thyroid Ca²⁺‐Dependent and NADPH‐Dependent K₃Fe(CN)₆ Reductase