<prompt> Wolff-chaikoff effect is ?Reduced thyroxine synthesis by radiotherapyReduced thyroxine synthesis by propylthiouracilReduced thyroxine synthesis by iodidesNone of the above  <response>: Ans. is c i.e., Reduced thyroxine synthesis by iodides Iodine and Iodides Iodine is the fastest acting thyroid inhibitor. Most impoant action is inhibition of hormone release thyroid constipation; but all facets of thyroid synthesis may be affected. Excess iodide inhibits its own transpo in thyroid cells and may alter the redox potential of cells, thus interfering iodination -reduced TIT3 synthesis Wolffichaikoff effect. 