Deiodinase enzymes and thyroid activity
Situation:
A person is hypotensive and is taking a synthetic T3 and T4 supplement. The dose is taken gradually and with modulated doses. Metabolism improves and fueling is better, but this only lasts for a short time. Why? Symptoms return:
"Feeling cold immediately after taking Cynoplus. What's going on?"
Impact of Iodine and Selenium Deficiency on Deiodinase Enzymes
Deiodinase enzymes are selenoproteins, meaning they require selenium to function properly. If the body is deficient in selenium, these enzymes may not be sufficiently active, which can disrupt the proper conversion of thyroid hormones. Furthermore, iodine is essential for the synthesis of thyroxine (T4), and an iodine deficiency can lead to insufficient T4 production, worsening hypothyroidism.
In such a situation, supplementing with T3 and T4 may temporarily improve symptoms, but if the body lacks the nutrients needed to properly activate or degrade these hormones (via DIO1, DIO2, and DIO3), the beneficial effects will be limited over time. In other words, taking T3 and T4 may only mask a deeper problem related to disturbed hormonal metabolism, rather than resolving the underlying cause.
Role of DIO enzymes
Three enzymes catalyzing deiodination have been identified, called type 1 (D1), type 2 (D2) and type 3 (D3) iodothyronine deiodinases. D1 and D2 have outer ring deiodinase activity, converting the prohormone T4 to its bioactive form T3 and degrading rT3 to 3,3’-T2. D3 has inner ring deiodinase activity and degrades T4 to rT3 and T3 to 3,3’-T2. (…)
Note (you can jump to next paragraph): 3,3’-T2 or 3,3'-Diiodo-L-thyronine is a metabolite of thyroid hormone that is also known as T2 or 3,3'-T2. It is derived enzymatically from triiodothyronine isoforms T3 and reverse T3. T2 plays many of the same roles as T3 but acts on different receptors. . Since there are no commercially available assays for T2, and T2 does not suppress TSH, its absence can contribute to hypothyroidism without being measurable.
https://thyroidspecificformulations.com/wp-content/uploads/2023/04/TSF-Factsheet-T2-T3-Converter.pdf
Combustion Engine Analogy
Let's imagine our metabolism as a car engine. If this engine runs on pistons without oil, this will lead to excessive friction, overheating, and eventually malfunction, even if the engine is still running. In this case, the oil represents the essential micronutrients (selenium, iodine, zinc, etc.) needed to properly activate and regulate the function of the enzymes that modify the combustion (or metabolism) of thyroid hormones.
Similarly, even if the car engine (our metabolism) continues to receive fuel (the T3 and T4 supplements), without the proper "lubricants" (the micronutrients), the engine will eventually run into problems. The intake of these micronutrients is essential to optimize the function of deiodinase enzymes and maintain metabolic hormonal balance.
To be continued on this link (in French, but with study references in English):
Micronutriments utiles au fonctionnement de la thyroïde (Useful nutrients for thyroid fuction)
https://mirzoune-ciboulette.forumactif.org/t2107-la-supplementation-en-hormones-thyroidiennes-masque-la-carence-en-iode#30191
Impact of iodine and selenium insufficiency on deiodinase enzymes in order to maintain a balanced hormonal metabolism.
Caution regarding iodine supplementation (to avoid the Wolff-Chaikoff effect).
The key to iodine supplementation is gradualness, allowing the body to adapt and avoid unwanted side effects.
Thyroid hormone supplementation (T3 & T4) masks iodine deficiency.
