Increased thyroidal T4 to T3 conversion in autonomously functioning thyroid adenoma: from euthyroidism to thyrotoxicosis.

Hdl Handle:
http://hdl.handle.net/10147/206268
Title:
Increased thyroidal T4 to T3 conversion in autonomously functioning thyroid adenoma: from euthyroidism to thyrotoxicosis.
Authors:
Solter, M; Posavec, L; Solter, D; Vargek-Solter, V
Affiliation:
Department of Endocrinology, Sisters of Mercy University Hospital Center,, University of Zagreb, School of Medicine, Vinogradska , Croatia., miljenkosolter@yahoo.com
Citation:
Ann Endocrinol (Paris). 2011 Jun;72(3):208-10. doi: 10.1016/j.ando.2011.04.008.
Journal:
Annales d'endocrinologie
Issue Date:
31-Jan-2012
URI:
http://hdl.handle.net/10147/206268
DOI:
10.1016/j.ando.2011.04.008
PubMed ID:
21640977
Abstract:
AIM: The aim was to investigate whether the intrathyroid conversion of T4 to T3 in autonomously functioning thyroid adenoma (AFTA) tissue could influence serum T3 levels and suppression of TSH, especially in patients with borderline thyroid function. PATIENTS AND METHODS: In ten patients with AFTA, thyroidal conversion of T4 to T3 was investigated in nodular and paranodular, TSH-suppressed tissue. All patients had normal serum T4 and suppressed TSH. Serum T3 was normal in six, and borderline or slightly increased in four. AFTA and paranodular tissues were surgically removed and frozen at -70 degrees C, then homogenized in a glass homogenizer, centrifuged at 100,000xg, and particulate fraction collected as a pellet. Analysis mixture consisted of thyroid enzyme suspension in 50 mumol/L TRIS buffer with 5 mumol DTT and 200 muL 1.3 mumol T4. Incubation was performed at 37 degrees C and the generation of T3 measured after 5, 10, 20 and 40 minutes respectively. RESULTS: T3 production (pmol/mg protein) was significantly higher in AFTA than in paranodular tissues (8.8 1.2/Mean +/- SE/vs. 1.8 +/- 0.2; p<0.01), and excessively high (9.8, 14.1, 14.2 and 15.0) in four patients with borderline or slightly supranormal serum T3. A significant correlation was found between serum T3 concentrations and T3 generation (T4 conversion) in AFTA tissues. CONCLUSION: Results suggest that increased thyroidal T4 to T3 conversion in AFTA tissue could be involved in an increased delivery of T3, increased serum T3 and suppressed serum TSH, particularly in patients with the disease evolving from euthyroid to an early hyperthyroid phase.
Language:
eng
MeSH:
Adenoma/*metabolism/surgery; Adult; Humans; Middle Aged; Thyroid Gland/*metabolism; Thyroid Neoplasms/*metabolism/surgery; Thyrotoxicosis/*metabolism; Thyrotropin/blood; Thyroxine/blood/*metabolism; Triiodothyronine/*biosynthesis/blood
ISSN:
0003-4266 (Print); 0003-4266 (Linking)

Full metadata record

DC FieldValue Language
dc.contributor.authorSolter, Men_GB
dc.contributor.authorPosavec, Len_GB
dc.contributor.authorSolter, Den_GB
dc.contributor.authorVargek-Solter, Ven_GB
dc.date.accessioned2012-01-31T16:39:53Z-
dc.date.available2012-01-31T16:39:53Z-
dc.date.issued2012-01-31T16:39:53Z-
dc.identifier.citationAnn Endocrinol (Paris). 2011 Jun;72(3):208-10. doi: 10.1016/j.ando.2011.04.008.en_GB
dc.identifier.issn0003-4266 (Print)en_GB
dc.identifier.issn0003-4266 (Linking)en_GB
dc.identifier.pmid21640977en_GB
dc.identifier.doi10.1016/j.ando.2011.04.008en_GB
dc.identifier.urihttp://hdl.handle.net/10147/206268-
dc.description.abstractAIM: The aim was to investigate whether the intrathyroid conversion of T4 to T3 in autonomously functioning thyroid adenoma (AFTA) tissue could influence serum T3 levels and suppression of TSH, especially in patients with borderline thyroid function. PATIENTS AND METHODS: In ten patients with AFTA, thyroidal conversion of T4 to T3 was investigated in nodular and paranodular, TSH-suppressed tissue. All patients had normal serum T4 and suppressed TSH. Serum T3 was normal in six, and borderline or slightly increased in four. AFTA and paranodular tissues were surgically removed and frozen at -70 degrees C, then homogenized in a glass homogenizer, centrifuged at 100,000xg, and particulate fraction collected as a pellet. Analysis mixture consisted of thyroid enzyme suspension in 50 mumol/L TRIS buffer with 5 mumol DTT and 200 muL 1.3 mumol T4. Incubation was performed at 37 degrees C and the generation of T3 measured after 5, 10, 20 and 40 minutes respectively. RESULTS: T3 production (pmol/mg protein) was significantly higher in AFTA than in paranodular tissues (8.8 1.2/Mean +/- SE/vs. 1.8 +/- 0.2; p<0.01), and excessively high (9.8, 14.1, 14.2 and 15.0) in four patients with borderline or slightly supranormal serum T3. A significant correlation was found between serum T3 concentrations and T3 generation (T4 conversion) in AFTA tissues. CONCLUSION: Results suggest that increased thyroidal T4 to T3 conversion in AFTA tissue could be involved in an increased delivery of T3, increased serum T3 and suppressed serum TSH, particularly in patients with the disease evolving from euthyroid to an early hyperthyroid phase.en_GB
dc.language.isoengen_GB
dc.subject.meshAdenoma/*metabolism/surgeryen_GB
dc.subject.meshAdulten_GB
dc.subject.meshHumansen_GB
dc.subject.meshMiddle Ageden_GB
dc.subject.meshThyroid Gland/*metabolismen_GB
dc.subject.meshThyroid Neoplasms/*metabolism/surgeryen_GB
dc.subject.meshThyrotoxicosis/*metabolismen_GB
dc.subject.meshThyrotropin/blooden_GB
dc.subject.meshThyroxine/blood/*metabolismen_GB
dc.subject.meshTriiodothyronine/*biosynthesis/blooden_GB
dc.titleIncreased thyroidal T4 to T3 conversion in autonomously functioning thyroid adenoma: from euthyroidism to thyrotoxicosis.en_GB
dc.contributor.departmentDepartment of Endocrinology, Sisters of Mercy University Hospital Center,, University of Zagreb, School of Medicine, Vinogradska , Croatia., miljenkosolter@yahoo.comen_GB
dc.identifier.journalAnnales d'endocrinologieen_GB
dc.description.provinceMunster-

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