Thyroid: Iodine Beyond the Thyronines

Although thyroid gland function is mainly under the control of pituitary TSH, other factors may also play a role in this process. Iodine is not used only by the thyroid to synthesize thyroid hormones but also directly influences a number of parameters such as thyroid proliferation and function. Thyroid autoregulation has been related to intraglandular content of an unknown putative iodocompound. The thyroid is capable of producing different iodolipids such as 6-iododeltalactone (ILδ) and 2-iodohexadecanal (2-IHDA). Data from different laboratories have shown that these iodolipids can inhibit several thyroid parameters suggesting that these compounds may be the intermediates in the thyroid autoregulation process.