Possible Interaction: Iodine and Triiodothyronine

“Patients from Group A … specific 131I activity of T3 and T4 showed lower specific … after addition of inactive iodine compared with patients from the same group with a lower initial specific 131I activity of … T4 and compared with the patient group B who was given no additional inactive iodide.”

“It is hypothesized that the maintenance of normal intrathyroidal HI is the result of the combined inhibitory effect of iodine on thyroid hormone synthesis and on the release of T4 and T3 from the thyroid.”

“Consecutive administration of iodine resulted in not only a reduction in serum levels of free triiodothyronine ( T3 ) but also an increase in serum levels of TRX in the patients.”

“The administration of iodine caused a rise in the mean serum T4, T3 , and free T4 concentrations in all three siblings, but did not alter the serum Tg concentration.”

“Low levels of iodine , observed in endemic goiter areas, decrease the synthesis of T3 and T4.”

“Thallium‐201 uptake, as well as serum thyroxine and triiodothyronine , fell significantly after treatment with iodine.”

“In 8 subjects with small or absent goiter there was a significant fall in T3 and a rise in TSH concentrations, suggesting an acute inhibitory effect of the iodine.”

“Combination of insulin I ) with hydrocortisone (H), T3 (T), or glucagon (G) resulted in a more than additive effect.”

“ T3 increased the mRNA content of the transcriptional co‐activator of mitochondrial genes, PGC‐1α, and the I and IV COX subunits in soleus.”

“Even just an extra of 35 mg iodine per day (adult horses, dry matter intake: 10 kg) can cause severe health risks, leading to enlarged thyroids and lowered triiodothyronine (T3) and thyroxine (T4) values (3).”