T4 storage

[serenfach]

I was stuck in a hedge (dont ask) and was thinking... I know T4 is the storage hormone and is converted to T3. But where is it stored? I googled it and it said Kidney. What? I have only got one dodgy kidney and this has never been mentioned.

A bit further digging said it was stored in the thyroid. But if you have had autoimmune thyroiditis for many years, do you still have a thyroid or is it a speck of dust? If you thyroid has been destroyed. where is the T4 stored?

This led on to the thought that if your thyroid is no longer there, why bother testing TSH? I eventually freed myself from the hedge (blackthorn hangs on tight!), so stopped thinking.

Any thoughts?

[tattybogle]

I think It is stored 'in the blood' by goblins

Thyroid Binding Globulins to be precise

Blackthorn ... ouch .

[helvella Administrator]

In someone with a working thyroid, some thyroid hormone will be present within the thyroid.

However, even that isn't as simple as appears. The whole process of taking in iodine and tyrosine, forming DIT and MIT, eventually making T4 and T3 means that a measure of any single part of that doesn't give a full picture.

However, as you rightly appreciate, if you have no working thyroid, that whole mechanism will not be functioning.

In the rest of our bodies, as tattybogle rightly said, a lot is attached to thyroid binding globulin in our blood.. But that doesn't mean it doesn't also get at least transiently "stored" in our liver, kidneys, muscle, etc., as well. Further, we can to some extent recycle thyroid hormone through processes of sulphation and glucoronidation, excretion and re-absorption.

[serenfach in reply to helvella]

Thanks. I left a fair bit of T4 in the hedge...

My liver seems to be in tip top condition, so I shall continue to help it along with the odd glass of Merlot

[pennyannie]

and without a thyroid I also believe since the feedback loop - the HPT axis - is now broken as the thyroid isn't there to complete this circuit - the TSH is a totally unreliable measure of anything.

I had RAI thyroid ablation in 2005 for Graves Disease so have no natural production and been switched from ' auto ' to ' manual ' and need to put my fuel in each day which is Natural Desiccated Thyroid.

The combined T3 and T4 thyroid hormones within the grain/tablet of NDT are attached to thyroglobulin and slowly released and absorbed in the body, mostly I think, in the liver.

[thyr01d]

Oh Serenfach, please do tell, how did you end up stuck in a hedge???!! I got stuck in a car once, in a petrol station, and was completely ignored by people filling their cars with fuel when waving and signalling to them to "let me out!".

[serenfach]

I was trimming the hedge. My hat got whipped off by an errant branch and I lent forward to get it before my ears fell off in the bitter wind. At that point, the hedge decided to take revenge and enveloped me - I swear I heard a giggle - and I am afraid I said a few naughty words which seemed to wither a branch, allowing me to escape after a while, minus hat and one glove. The thornproof gloves proved not to be thorn proof hence the loss of T4!