**5.4 TSHR agonists and antagonists**

The characteristics TSHR-Abs are stimulatory or inhibitory or neutral. In case of Hashimoto's thyroiditis, block the binding and action of TSH and, therefore, can cause hypothyroidism. Whereas in Graves' Disease, TSHR-Abs has both stimulating and blocking thereby the clinical presentation may manifest depend upon a balance between these different antibodies. In third category, TSHR-Abs is of the neutral variety which may bind to the receptor but not influencing thyroid stimulating hormone binding. However, these antibodies may not be entirely neutral and can have cell signaling capability of untoward changes [88].
