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Triiodothyronine, thyroxine, and iodine in purified thyroglobulin from patients with Graves' disease.
J Clin Invest. 1977 Jun; 59(6):1105-12.JCI

Abstract

Previous studies have suggested that there is an overproduction of triiodothyronine (T(3)) relative to thyroxine (T(4)) in patients with thyrotoxicosis associated with Graves' disease. To evaluate whether or not an increased ratio of T(3) to T(4) in thyroidal secretion could be contributing to this relative T(3) hyperproduction, T(3), T(4), and iodine were measured in thyroglobulin (Tg) from controls and patients with Graves' disease who had been treated either with propranolol only or with antithyroid drugs plus iodide before surgery. To avoid possible artifacts associated with pulse labeling and chromatography, T(3) and T(4) were determined by radioimmunoassay of Pronase hydrolysates of purified Tg. Results of analyses of Tg from six control patients and seven with Graves' disease, not receiving thiourea drugs or iodide, showed that the iodine content of Graves' disease Tg was not different from normal. Both contained 3.4 residues of T(4)/molecule Tg, but there was 0.39+/-0.08 (mean+/-SD) residue of T(3)/molecule Tg in Graves' Tg as opposed to 0.23+/-0.07 residue T(3) molecule Tg in controls matched for iodine content (P < 0.01). This difference resulted in a significantly lower T(4)/T(3) molar ratio (9+/-2) in Graves' Tg as opposed to control (15+/-2, P < 0.001). In Tg from patients with treated Graves' disease, iodine, T(3), and T(4) were reduced, but the reduction in the latter was more substantial, resulting in a T(4)/T(3) molar ratio of 3.4+/-1. Fractionation of Tg from all groups by RbCl density gradient ultracentrifugation indicated that at physiological levels of Tg iodination, the molar ratio of T(3)/Tg was consistently higher in Graves' disease. The specific mechanism for this difference is not known, but it is not due to iodine deficiency. If T(3) and T(4) are secreted in this altered ratio in patients with Graves' disease, the magnitude of the difference could explain the relative T(3) hyperproduction which is characteristic of this state.

Authors

No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

577211

Citation

Izumi, M, and P R. Larsen. "Triiodothyronine, Thyroxine, and Iodine in Purified Thyroglobulin From Patients With Graves' Disease." The Journal of Clinical Investigation, vol. 59, no. 6, 1977, pp. 1105-12.
Izumi M, Larsen PR. Triiodothyronine, thyroxine, and iodine in purified thyroglobulin from patients with Graves' disease. J Clin Invest. 1977;59(6):1105-12.
Izumi, M., & Larsen, P. R. (1977). Triiodothyronine, thyroxine, and iodine in purified thyroglobulin from patients with Graves' disease. The Journal of Clinical Investigation, 59(6), 1105-12.
Izumi M, Larsen PR. Triiodothyronine, Thyroxine, and Iodine in Purified Thyroglobulin From Patients With Graves' Disease. J Clin Invest. 1977;59(6):1105-12. PubMed PMID: 577211.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Triiodothyronine, thyroxine, and iodine in purified thyroglobulin from patients with Graves' disease. AU - Izumi,M, AU - Larsen,P R, PY - 1977/6/1/pubmed PY - 1977/6/1/medline PY - 1977/6/1/entrez SP - 1105 EP - 12 JF - The Journal of clinical investigation JO - J. Clin. Invest. VL - 59 IS - 6 N2 - Previous studies have suggested that there is an overproduction of triiodothyronine (T(3)) relative to thyroxine (T(4)) in patients with thyrotoxicosis associated with Graves' disease. To evaluate whether or not an increased ratio of T(3) to T(4) in thyroidal secretion could be contributing to this relative T(3) hyperproduction, T(3), T(4), and iodine were measured in thyroglobulin (Tg) from controls and patients with Graves' disease who had been treated either with propranolol only or with antithyroid drugs plus iodide before surgery. To avoid possible artifacts associated with pulse labeling and chromatography, T(3) and T(4) were determined by radioimmunoassay of Pronase hydrolysates of purified Tg. Results of analyses of Tg from six control patients and seven with Graves' disease, not receiving thiourea drugs or iodide, showed that the iodine content of Graves' disease Tg was not different from normal. Both contained 3.4 residues of T(4)/molecule Tg, but there was 0.39+/-0.08 (mean+/-SD) residue of T(3)/molecule Tg in Graves' Tg as opposed to 0.23+/-0.07 residue T(3) molecule Tg in controls matched for iodine content (P < 0.01). This difference resulted in a significantly lower T(4)/T(3) molar ratio (9+/-2) in Graves' Tg as opposed to control (15+/-2, P < 0.001). In Tg from patients with treated Graves' disease, iodine, T(3), and T(4) were reduced, but the reduction in the latter was more substantial, resulting in a T(4)/T(3) molar ratio of 3.4+/-1. Fractionation of Tg from all groups by RbCl density gradient ultracentrifugation indicated that at physiological levels of Tg iodination, the molar ratio of T(3)/Tg was consistently higher in Graves' disease. The specific mechanism for this difference is not known, but it is not due to iodine deficiency. If T(3) and T(4) are secreted in this altered ratio in patients with Graves' disease, the magnitude of the difference could explain the relative T(3) hyperproduction which is characteristic of this state. SN - 0021-9738 UR - https://www.unboundmedicine.com/medline/citation/577211/Triiodothyronine_thyroxine_and_iodine_in_purified_thyroglobulin_from_patients_with_Graves'_disease_ L2 - https://doi.org/10.1172/JCI108734 DB - PRIME DP - Unbound Medicine ER -