Effect of iodine on early stage thyroid autonomy

Thyroid autonomy is a frequent cause of thyrotoxicosis in regions with iodine deficiency. Epidemiological data suggest that the prevalence of thyroid autonomy is not only inversely correlated with the ambient iodine supply, but that iodide may also influence the course of pre-existing thyroid autonomy with possibly different effects on thyroid growth and function. Iodine slows TSH effects on thyroid growth stimulation and this effect is more pronounced in thyrocytes with constitutive cAMP activation i.e. in thyroid autonomy. Iodine induced growth alteration in early stage thyroid autonomy is conferred by induction of apoptosis and G2/M arrest. Transcriptome analysis revealed significant modulation of gene networks relevant to cell adhesion, cadherin signalling and ion binding with more pronounced effects in constitutively active FRTL-5 cells compared to normal FRTL-5 cells. The aim was to study iodide-induced changes in global gene expression in an in vitro model of thyroid autonomy. This model makes use of FRTL-5 cells with stable expression of a constitutively activating TSH receptor mutation or wild type TSHR as a control.