Quercetin was taken from an absolute ethanol stock solution; thus, control cells were treated with the same amount of vehicle. A critical review of food-associated factors proposed in the etiology of feline hyperthyroidism. Of the six flavonoid subgroups, flavonols and flavanols, isoflavones and flavanols, isoflavones and flavonols, and flavones and anthocyanidins were moderately to highly correlated Spearman correlation coefficient: 0. It has been shown that some flavonoids are able to increase iodide uptake and NIS expression in vitro, however, data in vivo are lacking.
Flavonoid is a class of natural aromatic compounds produced by plants, which are found in our daily diet, such as nuts, grains and fruits. Food and Chemical Toxicology , 50, Daniel R. In a great part of the differentiated carcinomas, thyrocytes are capable of uptaking iodide.
Thus, therapy with radioiodide becomes ineffective, limiting therapeutic options and reducing the life expectancy of the patient. In all experiments with quercetin, the medium was changed every 24 h adding fresh medium with quercetin. The data raise the possibility that quercetin may be a novel disruptor of thyroid function, which has potential effects on, or use in, the therapy of thyroid diseases. Preparation of whole-cell extracts and Western blotting To prepare whole-cell lysates, cells were collected, washed with ice-cold PBS, and resuspended in ice-cold lysis buffer [20 mm Tris-HCl pH 7. Published online Jun
Statistical analysis Spearman correlation coefficients were calculated to evaluate correlations between flavonoid subtypes among the entire study population. Toxicological Sciences , 2 , The flavonoid myricetin reduces nocturnal melatonin levels in the blood through the inhibition of serotonin N-acetyltransferase. Despite these beneficial properties, in , Divi and Doerge [ 10 ] demonstrated that rutin is able to inhibit TPO iodination activity in vitro.
Epidemiologic studies have linked high dietary intakes of flavonoids with reduced risks of multiple cancers 8. Compared to the lowest quintile of intake, participants in the top four quintiles were more likely to have a college education and less likely to be current smokers. American Journal of Therapeutics , 24 5 , ee Published online Jun
Inhibition by the more potent compounds, fisetin, kaempferol, naringenin, and quercetin, which contain a resorcinol moiety, was consistent with mechanism-based inactivation of TPO as previously observed for resorcinol and derivatives. None of the models were found to be in violation of the proportional hazards assumption.
Viable cell number was measured with a hemocytometer.
This article has been corrected. Main dietary sources of flavonoids included tea, citrus fruits and juices, legumes, and other fruits and vegetables supplementary table 1. Andrea C. See PLoS One. Fresh medium was added every 2—3 d, and cells were passaged every 7 d.