THE INHIBITION OF THE METABOLISM OF THIOCYANATE IN THE THYROID OF THE RAT<sup>1</sup>

Maloof, Farahe; Soodak, Morris

doi:10.1210/endo-65-1-106

Cited by 25 publications

(13 citation statements)

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“…Furthermore, it is highly unlikely that differences in the accumulation of S3.04--could have resulted from differing rates of its accumulation from the plasma. Previous studies of the nature of serum S35 after administration of S35CN-have shown negligible quantities of S350O--to be present (13), and administered S3504--is concentrated by the thyroid from the serum only slightly (21). Thus, it may be that the presently demonstrated ability of high doses of iodide to decrease the intrathyroidal conversion of SCN-to SOj--in rats adapted to iodide represents a reinduction of the Wolff-Chaikoff effect.…”

Section: Experiments and Resultsmentioning

confidence: 91%

“…Rats were killed, thyroids were quickly removed, frozen on dry ice, and weighed. Individual thyroid glands were then homogenized in 300 ,J of cold distilled water, and 25-ul samples were subjected to ascending filter-paper (Whatman 1 ) chromatography in a 1 M ethanol ammonium acetate (pH 7.5) system (7.7:3.0), as employed by Maloof and Soodak (13). Then, radioautographs were prepared, and from these, zones on the chromatograms corresponding to the 0-olodine-DeficienIConfro/s 0Adoptedtolodide point of application, to SCN-, and to sulfate were identified and excised.…”

Section: Experiments and Resultsmentioning

confidence: 99%

“…In an effort to assess the oxidative mechanisms of the control and adapted thyroids under conditions in which the specific activity of iodide would not, per se, influence measurements, the experiments with S35-labeled SCN-were undertaken. In the thyroid, SCN-is not actively concentrated (12,13), but it does undergo oxidation to yield protein-bound sulfur and sulfate (12,13,18). The oxidative mechanisms for SCN-and for iodide share many properties and may occur through a common mechanism.…”

Section: Experiments and Resultsmentioning

confidence: 99%

“…The oxidative mechanisms for SCN-and for iodide share many properties and may occur through a common mechanism. Both are inhibited by antithyroid agents, such as thiouracil derivatives (12,13,18), and both are stimulated by TSH (18). SCN-inhibits the oxidation of iodide (16,19).…”

Section: Experiments and Resultsmentioning

confidence: 99%

“…SCN-inhibits the oxidation of iodide (16,19). Furthermore, as for iodide, the oxidation of SCN-is acutely inhibited by single large doses of iodide, suggesting that the acute Wolff-Chaikoff effect is reflected in the metabolism of SCN- (13). Since endogenous concentrations of SCN-are small (20) and are not known to be influenced by variations in iodide intake, absolute rates of SCN-oxidation can be calculated from the specific activity of administered SCN-, even though extracellular iodide concentrations vary widely.…”

Section: Experiments and Resultsmentioning

confidence: 99%

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Changes in Thyroidal Function During Adaptation to Large Doses of Iodide*

Braverman¹,

Ingbar²

1963

J. Clin. Invest.

170

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In 1944, Morton, Chaikoff, and Rosenfeld first made the seemingly paradoxical observation that the addition of large quantities of inorganic iodide to suspending media inhibited the total incorporation of iodide into organic compounds by surviving slices of sheep thyroid gland (1). Four years later, Wolff and Chaikoff, whose names have come to designate this effect, demonstrated that a similar acute inhibitory response could be elicited in vivo by giving rats single doses of stable iodide sufficient to increase greatly the concentration of iodide in the plasma (2). As time passed and the concentration of iodide in the plasma declined below an apparently critical level, organic binding of iodine within the thyroid returned. Subsequently, it was shown that despite the maintenance of high plasma concentrations of iodide by the administration of repeated doses, inhibition of organic binding abated, and hormone formation resumed (3) ; this is the "escape" or "adaptation" phenomenon. Since the acute Wolff-Chaikoff effect occurs in man (4, 5), adaptation may also be presumed to occur, since the vast majority of patients given prolonged iodide therapy are able to maintain a euthyroid state.Since the initial description of the Wolff-Chaikoff effect, several additional facts and hypotheses concerning it have been presented. Raben, in a group of ingenious experiments, provided evidence that the acute inhibition of organic binding depends more closely upon the intrathyroidal than *

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Section: Experiments and Resultsmentioning

confidence: 91%

Section: Experiments and Resultsmentioning

confidence: 99%

Section: Experiments and Resultsmentioning

confidence: 99%

Section: Experiments and Resultsmentioning

confidence: 99%

Section: Experiments and Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Changes in Thyroidal Function During Adaptation to Large Doses of Iodide*

Braverman¹,

Ingbar²

1963

J. Clin. Invest.

170

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Thiocyanate overload and thyroid disease

Erdoğan

2003

BioFactors

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Thiocyanate [SCN-] is a complex anion which is a potent inhibitor of iodide transport. It is the detoxification product of cyanide and can easily be measured in body fluids. Consumption of naturally occurring goitrogens, certain environmental toxins and cigarette smoke can significantly increase SCN- concentrations to levels potentially capable of affecting the thyroid gland. Goiter endemics were reported to develop when the critical urinary iodine/ SCN- ratio decreases below 3 microg iodine per mg SCN-. Iodine supplementation completely reverses the goitrogenic influence of SCN-. SCN- is also generated from cigarette smoking as a detoxifying product of cyanide. During the past two decades many reports dealt with the possible effects of cigarette smoking on thyroid hormone synthesis, thyroid gland size and thyroid autoimmunity including infiltrative ophtalmopathy of Graves' disease. In this mini-review, issues regarding thiocyanate overload and thyroid disease will be summarized.

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Fortschrittsbericht Zur alimentären Aufnahme, Analytik und biologischen Bedeutung des Thiocyanats

Weuffen¹,

Franzke²,

Thürkow³

1984

Nahrung

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A survey is given of the alimentary ingestion, metabolization and elimination as well as of the biological significance of thiocyanate (SCN-) in the mammalian organism. SCN- is an important nutritional factor since it influences essential bodily functions, e.g. immune response. Its analytical determination in vegetable and animal foodstuffs may be considerably affected by the reversible binding of SCN- to protein molecules and by natural products, e.g. amino acids and cyanide, from glycosidic precursors, which interfere with the reaction with bromine. This will be combining paper chromatography with gas chromatography. Except Brassica species which are relatively high in SCN- in glycosidic combination, vegetable foodstuffs contain nearly 0.1-1.3 mg SCN-/kg fresh material; animal foodstuffs, e.g. beef, contains 0.5-0.7 mg SCN-/kg. Balances calculations have shown that in non-smokers the average alimentary ingestion ranges from 1.8 to 5.2 mg SCN-/d.

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THE INHIBITION OF THE METABOLISM OF THIOCYANATE IN THE THYROID OF THE RAT¹

Cited by 25 publications

References 0 publications

Changes in Thyroidal Function During Adaptation to Large Doses of Iodide*

Changes in Thyroidal Function During Adaptation to Large Doses of Iodide*

Thiocyanate overload and thyroid disease

Fortschrittsbericht Zur alimentären Aufnahme, Analytik und biologischen Bedeutung des Thiocyanats

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THE INHIBITION OF THE METABOLISM OF THIOCYANATE IN THE THYROID OF THE RAT1

Cited by 25 publications

References 0 publications

Changes in Thyroidal Function During Adaptation to Large Doses of Iodide*

Changes in Thyroidal Function During Adaptation to Large Doses of Iodide*

Thiocyanate overload and thyroid disease

Fortschrittsbericht Zur alimentären Aufnahme, Analytik und biologischen Bedeutung des Thiocyanats

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THE INHIBITION OF THE METABOLISM OF THIOCYANATE IN THE THYROID OF THE RAT¹