Iodide-Peroxidase Activity in Human Thyroid. I. Studies on Non-Toxic Nodular Goitre

Nièpomniszcze, Hugo; Altschuler, N; M, Korob; Degrossi, O

doi:10.1530/acta.0.0620193

Cited by 20 publications

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“…The digitonin treated suspension was centrifuged at 30 000 g for 60 min. The psedosolubilized enzyme activity was found to be present in the supernatant (Niepomniszcze et al 1969). …”

Section: Enzyme Preparationsmentioning

confidence: 98%

Effects of phenylbutazone on thyroid iodine metabolism in vitro

Targovnik

Gluzman

Coleoni

et al. 1980

Acta Endocrinologica

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Several alterations of thyroid function parameters have been reported in patients treated with phenylbutazone and we have studied the effect of this drug on the intrathyroidal iodine metabolism. An inhibition of the iodide transport expressed in terms of T/M ratios was observed in bovine thyroid slices incubated with high phenylbutazone concentrations. 10\m=-\3m produced 72% inhibition whereas lower concentrations showed no significant difference as compared with controls. Iodotyrosine synthesis was affected by 10\m=-\4m and 10\m=-\5m phenylbutazone. Formation of iodothyronine synthesis was markedly affected between 10\m=-\4m and 10\m=-\7m phenylbutazone concentrations. Thyroid peroxidase activity was measured by tyrosine-iodinase, triiodide and guaiacol assays. Soluble, pseudosolubilized and crude peroxidase preparations from bovine glands, as well as the soluble enzyme from human thyroids, have shown inhibition of tyrosine-iodinase activity when incubated with phenylbutazone in concentrations ranging from 10\m=-\3m to 10\m=-\8m, with a Ki of 4 \m=x\10\m=-\6m for bovine thyroid peroxidase and of 6 \m=x\10\m=-\6m for human soluble peroxidase. Formation of triiodide was affected between 10\m=-\3m and 10\m=-\8m phenylbutazone concentrations. Guaiacol peroxidation was scarcely affected by the action of the drug. We have concluded that phenylbutazone affects the intrathyroidal iodine metabolism through the inhibition of thyroid peroxidase in concentrations which are usually present in the sera of patients treated with this drug. Some patients treated with phenylbutazone have

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“…The digitonin treated suspension was centrifuged at 30 000 g for 60 min. The psedosolubilized enzyme activity was found to be present in the supernatant (Niepomniszcze et al 1969). …”

Section: Enzyme Preparationsmentioning

confidence: 98%

Effects of phenylbutazone on thyroid iodine metabolism in vitro

Targovnik

Gluzman

Coleoni

et al. 1980

Acta Endocrinologica

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“…Soluble thyroid peroxidase was prepared by treating the cell particles with trypsin, sodium deoxycholate and acetone as pre¬ viously reported (Covai Se Taurog 1967). Pseudo-solubilized peroxidase was obtained from the 30 000 g pellets by digitonin treatment (Niepomniszcze et al 1969). The thyroid supernatant obtained after centrifugation at 105 000 g was used for thyro¬ globulin purification and to study the radioiodo-amino acid distribution.…”

Section: Tissue Preparationsmentioning

confidence: 99%

Biochemical Studies on the Iodine Organification Defect of Pendred's Syndrome

Nièpomniszcze¹,

Ah²,

Degrossi³

et al. 1978

Acta Endocrinologica

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Biochemical studies were performed on the thyroid of a typical case of Pendred's syndrome who underwent total thyroidectomy. The patient, a euthyroid 14 year old female, presented congenital nerve deafness, goitre and impairment of thyroidal iodine organification. Thyroid peroxidase (TPO) activity was quantitatively normal. Using crude preparations, enzyme activity ranged from 176\p=n-\366 nmoles of I \ m= -\ \ x = r e q -\ incorporated (inc.) to tyrosine/g of tissue. Normal values are 220\p=n-\410 nmoles I\m=-\inc./g. Digitonin pseudosolubilized TPO, assayed by the tyrosine-iodinase method, showed 44.9 nmoles I\m=-\ inc./mg of protein for the Pendred's tissue, and 44.5 nmoles I\m=-\ inc./mg for the control glands. Soluble TPO was utilized for enzyme-kinetic studies. The Km for H2O2, obtained in the triiodide assay with iodide as hydrogen donor, was in the same order of magnitude for both Pendred's and control thyroids, being 3 \ m=x\ 10\m=-\4 m and 3.5 \ m=x\10\m=-\4 m, respectively. In the guaiacol assay, the Pendred's Km value of 4 \ m=x\10\m=-\4 m was also normal for H2O2. Pre-incubation of enzyme preparations with 5 \m=x\10\m=-\5m haematin did not stimulate TPO activity. Thyroidal NADPH-cytochrome c reductase and monoamine oxidase activities were normal. A low concentration, 37 mg/g, of a qualitatively normal thyroglobulin was found in Pendred's goitre. The iodine content of thyroglobulin was 0.19 %.

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“…However, in the present experi- (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). In nontoxic nodular goiter, the activity is decreased in cold nodules and increased or remained the same as normal tissue in warm nodules (11,12). In goiters with an iodide organification defect, peroxidase activity is usually decreased (12)(13)(14)(15)(16)(17), but is normal in Pendred's syndrome (18,19).…”

Section: Discussionmentioning

confidence: 50%

“…Whereas a direct effect of antithyroid drugs can not be ruled out, the peroxidase activity was not changed when rats were sacrificed 1 h after the injection of propylthiouracil (6), although methimazole may behave differently from propylthiouracil (10). However, in the present experi- (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). In nontoxic nodular goiter, the activity is decreased in cold nodules and increased or remained the same as normal tissue in warm nodules (11,12).…”

Section: Discussionmentioning

confidence: 54%

Iodinating activity of thyroid tissue in toxic diffuse goiter.

Nagataki¹,

Uchimura²,

Ikeda³

et al. 1977

J. Clin. Invest.

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A B S T R A C T Thyroid tissue obtained from 12 patients with Graves' disease and treated with thionamide drugs for 3-7 mo before subtotal thyroidectomy, from 12 patients with Graves' disease, similarly treated, and given 50 ,ug of triiodothyronine (T3) for 10 days before surgery, and from 12 euthyroid patients with solitary cold nodules was investigated to compare in vitro iodination of thyroglobulin in toxic diffuse goiter and in normal thyroid tissue. The supernates of the homogenates (105,000g) were subjected to sucrose density gradient centrifugation (5-28%) to separate the thyroglobulin fraction. The precipitates were treated with 1% digitonin and centrifuged to collect the supernate (particulate fraction). When thyroglobulin and particulate fractions obtained from the same patient were incubated with 125I-, iodide, glucose, and glucose oxidase, the amount of iodine bound to thyroglobulin was several times greater in toxic diffuse goiter than in normal thyroid tissue; administration of T3 did not affect iodination in toxic diffuse goiter. When the thyroglobulin fraction from each patient was incubated with a standardized quantity of peroxidase instead of the individual particulate fraction, the amount of iodine bound to thyroglobulin was the same among the three groups of patients. Finally, when bovine serum albumin was substituted for thyroglobulin from each of the patients, iodination of bovine serum albumin was several times greater with the particulate fraction obtained from toxic diffuse goiter tissue than with that obtained from normal

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Iodide-Peroxidase Activity in Human Thyroid. I. Studies on Non-Toxic Nodular Goitre

Cited by 20 publications

References 0 publications

Effects of phenylbutazone on thyroid iodine metabolism in vitro

Effects of phenylbutazone on thyroid iodine metabolism in vitro

Biochemical Studies on the Iodine Organification Defect of Pendred's Syndrome

Iodinating activity of thyroid tissue in toxic diffuse goiter.

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