Thyroxine (T<sub>4</sub>) and Triiodothyronine (T<sub>3</sub>): Effects of Iodine on the Serum Concentrations and Disposal Rates in Subjects from an Endemic Goiter Area

Stevenson, C; Silva, Enrique; G, Pineda

doi:10.1210/jcem-38-3-390

Cited by 26 publications

(13 citation statements)

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“…Other factors that might modify the serum T 3 concentration have not been carefully studied. Thus, the MCR of T 3 in goitrous subjects has been reported to be increased (24) or unchanged (23). Peripheral deiodination of T 4 to T 3 has not been investigated in goitrous subjects.…”

Section: Discussionmentioning

confidence: 99%

Goiter Size and Thyroid Function in an Endemic Goiter Area in Northern Italy *

Roti

Gardini

d’Amato

et al. 1986

The Journal of Clinical Endocrinology & Metabolism

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Thyroid function was studied in a large number of subjects residing in Varsi, a town in the province of Parma, Italy. In this area, endemic goiter associated with moderate iodine deficiency [59 +/- 3 (+/- SE) microgram iodine/g creatinine], as defined by WHO criteria, affects 65% of the population. Serum T4, T3, thyroglobulin (Tg), and TSH concentrations were measured by RIA in 1218 subjects. The TSH response to TRH was determined in 108 subjects selected randomly from the groups with different grades of goiter. No significant change in serum T4 concentrations was found in subjects with different grades of goiter. Serum T3 concentrations were higher in subjects with the larger goiters. Serum Tg concentration progressively increased, and serum TSH progressively decreased with increasing goiter size. The TSH response to TRH was diminished in subjects with larger goiters. The findings of decreasing serum TSH concentrations and blunted TSH responses to TRH as goiter size increased suggest the possibility of autonomous thyroid function in the larger goiters in subjects residing in this area of moderate iodine deficiency.

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Section: Discussionmentioning

confidence: 99%

Goiter Size and Thyroid Function in an Endemic Goiter Area in Northern Italy *

Roti

Gardini

d’Amato

et al. 1986

The Journal of Clinical Endocrinology & Metabolism

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“…The common effect of iodine deficiency in adults is endemic goitre and the typical patient is not clinically hypothyroid, but many have a low serum thyroxine. This is often accompanied by a normal or elevated T3 concentration and a raised TSH (Stevenson et al, 1974;Medeiros-Neto et al, 1975;Chopra et al, 1975;Hershman et al, 1983) and normal or exaggerated TSH response to TRH (Medeiros-Neto et a /., 1975). A mild increase in the incidence of thyrotoxicosis has been reported after iodized salt correlated significantly (r=0,72, P<O.OOl) with the size and weight of goitre.…”

Section: Discussionmentioning

confidence: 99%

Transient Thyrotoxicosis in Endemic Goitre Patients Following Exposure to a Normal Iodine Intake

Lima

Medeiros‐Neto

1984

Clinical Endocrinology

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Twenty-three endemic goitrous subjects (goitre grade: III and IV) that were living in a chronic iodine-deficient area (iodine intake: less than 40 micrograms I/d) were submitted to clinical and laboratory evaluation within 3-8 weeks of arrival at the metropolitan area of São Paulo, where daily iodine intake is estimated to be 150-200 micrograms I/d. Eight patients developed a mild thyrotoxic state (T4 = 14.7 +/- 2.3 micrograms/dl, T3 = 279 +/- 55 ng/dl, no TSH response to TRH). Five additional subjects, although euthyroid, had a blunted TSH-response to TRH, and the remaining ten patients were euthyroid and had a normal TSH response to TRH. Thyrotoxicosis was associated with larger goitres (mean thyroid weight: 133 +/- 46 g), with high thyroid uptake of RAI (mean 24 h 131I uptake: 40 +/- 15%) but not with increased urinary iodine excretion. Serum Tg levels were more elevated in the first two groups of patients (respectively, geometric means 68 and 72 ng/ml), than in the euthyroid, TRH-responsive group (52 ng/ml). Thyrotoxicosis resolved spontaneously after three to six months without the need for any specific medication. It was concluded that a relatively small and normal iodide intake due to regular consumption of iodized salt and industrialized foods may induce a transient form of thyrotoxicosis in endemic goitre patients arriving into urban areas.

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“…In severe iodine deficiency, the thyroid may not be able to compensate the inadequate supply of iodine and the loss of iodide in the urine, so the T4 levels may greatly decrease. Only rarely, in very severe deficiency, do T3 levels also decrease and cause hypothyroidisim (Goslings et al, 1976); in fact, they often increase (Stevenson et al, 1974, Pate1 et al, 1973.…”

Section: Goitre As a Consequence Of Iodine Deficiency And Other Nutrimentioning

confidence: 99%

“…All these consequences of iodine deficiency, except for the large goitres, are reversible after iodine administration (Thilly et al, 1973;Stevenson et al, 1974;Denef et al, 1989).…”

Section: Goitre As a Consequence Of Iodine Deficiency And Other Nutrimentioning

confidence: 99%

Large goitre as a maladaptation to iodine deficiency

Dumont¹,

Ermans²,

Maenhaut³

et al. 1995

Clinical Endocrinology

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Thyroxine (T₄) and Triiodothyronine (T₃): Effects of Iodine on the Serum Concentrations and Disposal Rates in Subjects from an Endemic Goiter Area

Cited by 26 publications

References 0 publications

Goiter Size and Thyroid Function in an Endemic Goiter Area in Northern Italy *

Goiter Size and Thyroid Function in an Endemic Goiter Area in Northern Italy *

Transient Thyrotoxicosis in Endemic Goitre Patients Following Exposure to a Normal Iodine Intake

Large goitre as a maladaptation to iodine deficiency

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Thyroxine (T4) and Triiodothyronine (T3): Effects of Iodine on the Serum Concentrations and Disposal Rates in Subjects from an Endemic Goiter Area

Cited by 26 publications

References 0 publications

Goiter Size and Thyroid Function in an Endemic Goiter Area in Northern Italy *

Goiter Size and Thyroid Function in an Endemic Goiter Area in Northern Italy *

Transient Thyrotoxicosis in Endemic Goitre Patients Following Exposure to a Normal Iodine Intake

Large goitre as a maladaptation to iodine deficiency

Contact Info

Product

Resources

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Thyroxine (T₄) and Triiodothyronine (T₃): Effects of Iodine on the Serum Concentrations and Disposal Rates in Subjects from an Endemic Goiter Area