STUDIES OF THYROID HORMONE SYNTHESIS IN EXPERIMENTAL AUTOIMMUNE THYROIDITIS

ABSTRACT Thyroid hormone synthesis in rabbits with experimentally induced thyroiditis is compared with hormone synthesis in normal rabbits and in immunized rabbits receiving thyroid stimulating hormone. The immunized rabbits showed decreased thyroidal accumulation rates for 131I. T. S. H. administration produced an increase in the accumulation rate of immunized animals, but this increase was smaller than that obtained in normal rabbits stimulated with T. S. H. None of the rabbits' thyroids discharged iodide with the administration of potassium thiocyanate. Twenty-four and 48 hours after 131I was administered, chromatography was performed on digested extracts of the thyroid glands. In the digested extracts of thyroids removed from normal rabbits the mono:diiodotyrosine ratio was greater than 1.0 whereas the extracts of thyroids removed from immunized rabbits and normal rabbits stimulated with T. S. H. consistently had a ratio of less than 1.0. Thyroxine was not always present in the thyroids of normal rabbits but was consistently found in the thyroids of the immunized and T. S. H. treated animals. These findings suggest that the remaining thyroid cells in the glands of immunized rabbits are operating under increased T. S. H. stimulation. The experimental thyroiditis of immunized rabbits was similar to Hashimoto's thyroiditis in respect to histological alteration and the presence of anti-thyroid antibodies. 131I accumulation rates, response to potassium thiocyanate, and chromatography studies revealed no correlation between the two groups.

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Thyroid hormone synthesis in thyroglobulin secreted by porcine thyroid cells cultured on porous bottom chambers. Effect of iodide.

Endocrinology ◽

10.1210/endo.131.6.1446629 ◽

1992 ◽

Vol 131 (6) ◽

pp. 2921-2927 ◽

Cited By ~ 8

Author(s):

D Gruffat ◽

N Venot ◽

C Marriq ◽

O Chabaud

Keyword(s):

Thyroid Hormone ◽

Thyroid Cells ◽

Hormone Synthesis ◽

Thyroid Hormone Synthesis ◽

Cells Cultured

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Association of Duoxes with Thyroid Peroxidase and Its Regulation in Thyrocytes

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2009-1727 ◽

2010 ◽

Vol 95 (1) ◽

pp. 375-382 ◽

Cited By ~ 53

Author(s):

Yue Song ◽

Jean Ruf ◽

Philippe Lothaire ◽

Didier Dequanter ◽

Guy Andry ◽

...

Keyword(s):

Thyroid Hormone ◽

Protein Kinase ◽

Plasma Membranes ◽

Cell Damage ◽

Thyroid Tissue ◽

Human Thyroid ◽

Thyroid Peroxidase ◽

Thyroid Cells ◽

Hormone Synthesis ◽

Thyroid Hormone Synthesis

Abstract Context: Thyroid hormone synthesis requires H2O2 produced by dual oxidases (Duoxes) and thyroperoxidase (TPO). Defects in this system lead to congenital hypothyroidism. H2O2 damage to the thyrocytes may be a cause of cancer. Objective: The objective of the study was to investigate whether Duox and TPO, the H2O2 producer and consumer, might constitute a complex in the plasma membrane of human thyroid cells, thus maximizing efficiency and minimizing leakage and damage. Design: The interaction between Duox and TPO was studied by coimmunoprecipitation and Western blotting of plasma membranes from incubated follicles prepared from freshly resected human thyroid tissue from patients undergoing thyroidectomy, and COS-7 cells transiently transfected with the entire Duoxes or truncated [amino (NH2) or carboxyl (COOH) terminal]. Results: The following results were reached: 1) Duox and TPO from membranes are coprecipitated, 2) this association is up-regulated through the Gq-phospholipase C-Ca2+-protein kinase C pathway and down-regulated through the Gs-cAMP-protein kinase A pathway, 3) H2O2 increases the association of Duox1 and Duox2 to TPO in cells and in membranes, and 4) truncated NH2- or COOH-terminal Duox1 and Duox2 proteins show different binding abilities with TPO. Conclusion: Coimmunoprecipitations show that Duox and TPO locate closely in the plasma membranes of human thyrocytes, and this association can be modulated by H2O2, optimizing working efficiency and minimizing H2O2 spillage. This association could represent one part of a postulated pluriprotein complex involved in iodination. This suggests that defects in this association could impair thyroid hormone synthesis and lead to thyroid insufficiency and cell damage.

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BIOCHEMICAL DEFECTS IN THYROID HORMONE SYNTHESIS AND THEIR RELATION TO ENDEMIC GOITER

Acta Endocrinologica ◽

10.1530/acta.0.074s034 ◽

1973 ◽

Vol 74 (2_Suppla) ◽

pp. S34-S44

Author(s):

Leslie J. DeGroot

Keyword(s):

Thyroid Hormone ◽

Endemic Goiter ◽

Hormone Synthesis ◽

Thyroid Hormone Synthesis

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THE INFLUENCE OF THE PLASMA INORGANIC IODINE CONCENTRATION ON THYROID FUNCTION IN DEHALOGENASE DEFICIENCY

Acta Endocrinologica ◽

10.1530/acta.0.0550361 ◽

1967 ◽

Vol 55 (2) ◽

pp. 361-368 ◽

Cited By ~ 3

Author(s):

R. McG. Harden ◽

W. D. Alexander ◽

S. Papadopoulos ◽

M. T. Harrison ◽

S. Macfarlane

Keyword(s):

Thyroid Hormone ◽

Thyroid Function ◽

Iodine Concentration ◽

Rapid Rise ◽

Normal Range ◽

Hormone Synthesis ◽

Thyroid Hormone Synthesis ◽

Iodine Metabolism ◽

Inorganic Iodine ◽

Circulating Levels

ABSTRACT Iodine metabolism and thyroid function were studied in a patient with hypothyroidism and goitre due to dehalogenase deficiency. Initially the plasma inorganic iodine (PII) level was within the normal range but circulating levels of hormone were low and the thyroid clearance and absolute uptake of iodine (AIU) by the thyroid were high. Administration of iodide supplements resulted in a rapid rise in the plasma thyroxine concentration and restoration of the euthyroid state. Thyroid hormone synthesis appeared to proceed normally when the PII exceeded 1.0 μg/100 ml. This was achieved by increasing the intake of iodide by 612 μg per day. At PII levels around 10 μg/100 ml there was evidence of increased levels of circulating thyroid hormone.

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