CONTEXT: Graves' hyperthyroidism and multinodular toxic goiter lead to high serum T(3) compared with serum T(4). The source of this high T(3) has not been clarified. OBJECTIVE: Our objective was to assess the role of iodothyronine deiodinase type 1 (D1) and type 2 (D2) for T(3) production and to estimate the sources of T(3) in hyperthyroidism. DESIGN AND SETTING: The study was a prospective, randomized, open-labeled study in a secondary care setting. PATIENTS AND METHODS: Consecutive patients with hyperthyroidism caused by Graves' disease or by multinodular toxic goiter were randomized to be treated with high-dose propylthiouracil (PTU) to block D1, PTU plus KI, or PTU plus sodium ipodate to additionally block D2. T(3) and T(4) were measured in serum, and we estimated the sources of T(3). RESULTS: PTU reduced the T(3)/T(4) in serum to 47.7 +/- 2.5% (mean +/- sem) of the initial value on d 4 of therapy in patients with Graves' disease. The addition of KI to PTU led to a greater fall in T(3) and T(4), but the balance was unaltered. After PTU plus ipodate, T(3)/T(4) on d 4 was lower, 34.1 +/- 1.2% of the initial value. Similar variations were observed in patients with multinodular toxic goiter. Thus, the major source of the excess T(3) was D1-catalyzed T(4) deiodination, with a minor role for D2. It was estimated that the majority of this D1-catalyzed T(3) production takes place in the hyperactive thyroid gland. CONCLUSION: Although thyroidal T(3) contributes only around 20% of total T(3) production in normal individuals, this is much higher in patients with a hyperactive thyroid, ranging up to two thirds. The major part is produced from T(4) deiodinated in the thyroid.
RCT Entities:
CONTEXT: Graves' hyperthyroidism and multinodular toxic goiter lead to high serum T(3) compared with serum T(4). The source of this high T(3) has not been clarified. OBJECTIVE: Our objective was to assess the role of iodothyronine deiodinase type 1 (D1) and type 2 (D2) for T(3) production and to estimate the sources of T(3) in hyperthyroidism. DESIGN AND SETTING: The study was a prospective, randomized, open-labeled study in a secondary care setting. PATIENTS AND METHODS: Consecutive patients with hyperthyroidism caused by Graves' disease or by multinodular toxic goiter were randomized to be treated with high-dose propylthiouracil (PTU) to block D1, PTU plus KI, or PTU plus sodium ipodate to additionally block D2. T(3) and T(4) were measured in serum, and we estimated the sources of T(3). RESULTS:PTU reduced the T(3)/T(4) in serum to 47.7 +/- 2.5% (mean +/- sem) of the initial value on d 4 of therapy in patients with Graves' disease. The addition of KI to PTU led to a greater fall in T(3) and T(4), but the balance was unaltered. After PTU plus ipodate, T(3)/T(4) on d 4 was lower, 34.1 +/- 1.2% of the initial value. Similar variations were observed in patients with multinodular toxic goiter. Thus, the major source of the excess T(3) was D1-catalyzed T(4) deiodination, with a minor role for D2. It was estimated that the majority of this D1-catalyzed T(3) production takes place in the hyperactive thyroid gland. CONCLUSION: Although thyroidal T(3) contributes only around 20% of total T(3) production in normal individuals, this is much higher in patients with a hyperactive thyroid, ranging up to two thirds. The major part is produced from T(4) deiodinated in the thyroid.
Authors: Suyeon Park; Eyun Song; Hye-Seon Oh; Mijin Kim; Min Ji Jeon; Won Gu Kim; Tae Yong Kim; Young Kee Shong; Doo Man Kim; Won Bae Kim Journal: Endocrine Date: 2019-06-24 Impact factor: 3.633
Authors: Francesco S Celi; Giuseppe Coppotelli; Aaron Chidakel; Marilyn Kelly; Beth A Brillante; Thomas Shawker; Natasha Cherman; Penelope P Feuillan; Michael T Collins Journal: J Clin Endocrinol Metab Date: 2008-03-18 Impact factor: 5.958
Authors: Balázs Gereben; Ann Marie Zavacki; Scott Ribich; Brian W Kim; Stephen A Huang; Warner S Simonides; Anikó Zeöld; Antonio C Bianco Journal: Endocr Rev Date: 2008-09-24 Impact factor: 19.871
Authors: Eleni M Domouzoglou; Ffolliott Martin Fisher; Inna Astapova; Elliott C Fox; Alexei Kharitonenkov; Jeffrey S Flier; Anthony N Hollenberg; Eleftheria Maratos-Flier Journal: Endocrinology Date: 2014-02-24 Impact factor: 4.736
Authors: Antonio C Bianco; Alexandra Dumitrescu; Balázs Gereben; Miriam O Ribeiro; Tatiana L Fonseca; Gustavo W Fernandes; Barbara M L C Bocco Journal: Endocr Rev Date: 2019-08-01 Impact factor: 19.871
Authors: Valmara S Pereira; Michelle P Marassi; Doris Rosenthal; Mário Vaisman; Vânia M Corrêa da Costa Journal: Endocrine Date: 2011-12-30 Impact factor: 3.633