THE FLAVONOID QUERCETIN INHIBITS THYROID FUNCTION IN RATS

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 437-470-Non-neoplastic Thyroid Disorders
Basic/Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-458
Cesidio Giuliani*1, Serena Di Santo1, Ines Bucci1, Mauro Piantelli1, Alessandra De Remigis2, Fabrizio Monaco1 and Giorgio Napolitano1
1University of Chieti-Pescara, Chieti, Italy, 2Johns Hopkins University, Baltimore, MD
Quercetin is the most abundant dietary flavonoid present in fruits and vegetables. A daily intake between 20 and 40 mg has been estimated and up to 200-500 mg/day can be ingested. Furthermore, Quercetin is available as dietary supplemental and ingestion of 1 g/day or even more, has been reported. Several studies have shown that Quercetin and other flavonoids possess many therapeutically relevant properties as induction of apoptosis in tumor cells, antiviral, antioxidant, anti-inflammatory and antiproliferative activities. Beside these positive health effects, potential side effects should be considered in case of excessive intake. Indeed, flavonoids have potent antithyroid properties. In a previous report we have shown that the treatment with Quercetin of the rat thyroid cell lines FRTL-5, inhibited cell growth, iodide uptake and sodium-iodide symporter (NIS) gene expression. We further investigated the effect of Quercetin on thyroid gene expression performig Northern blotting, Western blotting and ELISA. and we showed that this compound downregulated the expression of others thyroid-restricted genes, as TSH receptor (TSHR), thyroid peroxidase (TPO) and thyroglobulin (TG). To confirm in vivo the antithyroid effect of Quercetin observed in the FRTL-5 cells, we evaluated the radioiodine uptake (RAIU) in Sprague-Dawley rats. Twelve rats were treated for 14 days with Quercetin 50 mg/Kg i.p. After treatment, Na125I was administerd i.p. and RAIU was evaluated after 24 hours. The treatment with Quercetin significantly decreased RAIU. These data indicate a potential role of Quercetin as a thyroid disruptor and suggest further studies to evaluate its use in hyperthyroidism.

Nothing to Disclose: CG, SD, IB, MP, AD, FM, GN

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