Low Thyroid in 21 Lessons (Article 4)

Hello,

I am Dr Michael Teplisky, a holistic medical doctor from Low Thyroid Doctor.com and this is lecture 4 in our seminar about low thyroid called “Hypothyroidism in 21 Lectures.” 

So far, we have learned that thyroid gland makes hormones T3 and T4, these hormones regulate the metabolism and energy production in all the cells of the body. And ideally, thyroid produces just the right amount of these hormones.    

The question is, how does the thyroid gland know how many hormones to make? It turns out that there is a very sophisticated system designed to regulate the production and distribution of the thyroid hormones. 

First, the thyroid has a direct boss that issues instructions and orders.

The name of this boss is pituitary gland, which is located inside the brain. In other words, the pituitary is part of the brain. The pituitary actually regulates quite a few endocrine glands in the body, including adrenal glands, testicles, ovaries, and some others. But for our purposes, the pituitary gland regulates the thyroid by producing a hormone called TSH or Thyroid Stimulating Hormone. TSH is also called thytrophin. So TSH and thytrophin are the same thing. What TSH does, It travels from the pituitary to the thyroid gland and it stimulates all the phases of the hormone production. TSH makes the thyroid gland produce more T3 and T4.

But that’s not all. The pituitary gland is not the ultimate boss of the thyroid. There is another part of the brain, it is called hypothalamus and it produces a hormone that regulates the pituitary. The hormone is called TRH, thytrophin releasing hormone. It stimulates the production of TSH, which stimulates the thyroid and increases T3 and T4.

So far, pretty simple. Hypothalamus controls the pituitary, which in turn controls the thyroid gland. So ultimately, it’s the brain that decided how much T3 and T4 should be produced. 

Then, there is another mechanism that is called negative feedback. The levels of T3 and T4 also affect the TSH, so if there is too much thyroid hormones, TSH production goes down. And if the level of T3 and T4 is low, the production of TSH will go up, to stimulate more thyroid activity. In other words, they typically move in opposite directions.   

Thyroid gland produces mostly T4, about 80% and only 20% is T3. To put it another way, there is 4 to 1 ratio of T4 to T3. We’ll talk more about it in a later lecture, but for now let me explain why there are 2 thyroid hormones. The reason is that only one of them is active. That’s T3. T4 is used as a ready source for creating T3 when the body needs it. 

By now we’ve learned that thyroid hormones are made inside the thyroid gland. But what happens to them once they are made? Most of them remain inside the thyroid. At any given time, the thyroid gland contains a month-worth or more of the thyroid hormones, to be released into the blood when needed.

The thyroid hormones that do not stay in the thyroid gland are released directly into the blood. Almost all the T3 and T4 that go into the blood are attached to special proteins. There are several such proteins and they can be measured in the blood. We don’t normally check them, but we do in some situations. About 99% of T3 and T4 in the blood are attached to proteins and they are called “bound”. 

Proteins transport the thyroid hormones throughout the body, they make sure that the hormones are available everywhere in the body and they release the hormones as needed.

Only 1% of the thyroid hormones in the blood is not attached to proteins, and they are called “free” hormones, free T4 and free T3. Out of the two, it is free T3 that is active and does all the work. 

When the body needs more free T3, it makes it from free T4. When the level of free hormones drops, some of the hormones that are bound to proteins are released and become free.  At this point, some hormones that are stored inside the thyroid gland are released to replace those that were given up by the proteins. And new hormones are made by the thyroid to replace those that leave the gland. 

To put it another way, thyroid hormones are so important, that they are not only very tightly regulated, but there is a very sophisticated system to regulate them. 

The brain produces not one but two different hormones to tell the thyroid what to do and how many thyroid hormones to produce, how many to store inside, how many to release into the blood. The body makes sure that there are free hormones available for Immediate action and there is a large supply of thyroid hormones in the blood, bound to proteins but available to be released as needed. 

Plus, there is a negative feedback mechanism, which lowers TSH when there is enough T4 and T3, and raises TSH when thyroid hormone are low.

In other words, when things are working properly, the way they were designed to work, there is plenty of thyroid hormones in various stages of readiness.

OK, today we talked about thyroid control and regulation and how thyroid hormones are kept in abundance, so the cells of the body have plentiful supply. We also learned that T3 is the active hormone and it is made from T4.  

Next time I’ll talk about turning T4 into T3, how it is done, what is needed for that to happen, what can improve this process and what can make it worse, which can lead to low thyroid. 

Please make sure to subscribe to my newsletter which you will get about once a week. If you know someone who might find this information useful, please forward it to them. Also, if you have questions or comments, please email to info@LowThyroidDoctor.com. I try to read and answer all of them, time permitting.  

Also, please keep in mind that if you suspect that you have low thyroid or you are being treated and are not getting better, you can get a free, no obligation 30 min phone consultation with me to see if I can help you get better. Just book it online or call my office at 718-769-0997. 

I’ll see you in the next lecture. 

Until then, I am Dr. Michael Teplisky from LowThyroidDoctor.com wishing you the best of health.