Interference in the use of T4 as thyroid therapy

[diogenes]

This downloadable paper discusses what factors might interfere with T4 uptake in therapy and how to disentangle the various possibilities. It only barely touches on FT3 - as is still the fashion.

Full-text available

Factors influencing the levothyroxine dose in the hormone replacement therapy of primary hypothyroidism in adults

October 2021Reviews in Endocrine and Metabolic Disorders Follow journal

DOI: 10.1007/s11154-021-09691-9

Philippe Caron, Solange Grunenwald, Luca Persani, Leonidas Duntas et al

[helvella]

This link appears to work: link.springer.com/article/1...

[helvella]

In Figure 2, it mentions (top left) "ETHER BOND CLEAVAGE" where an etherase is claimed to act on thyroxine T4 and produce diiodotyrosines.

As this was new to me, I tried to find any more information but found nothing. I didn't find any of the references appeared promising (not that I can access most of them), nor PubMed, nor Google.

Do you have any more information?

[pennyannie in reply to helvella]

My lap top cut itself off twice trying to process the full article, so I'll wait for a translation in layman' s terms and just follow this dialogue!!

[diogenes Remembering in reply to helvella]

There is quite a bit of literature discussing the cleavage of the ether (-O-) linkage of phenylbenzyl ether. So it's not a long shot to suppose that there are similar etherases that cleave the same bond in T4 to produce two T2 molecules.

[helvella in reply to diogenes]

Thank you, diogenes.

[DippyDame]

My thoughts in passing!

Might help if practitioners were skilled in evaluating full thyroid labs.

Scare mongering... and accusations of patient non- compliance may not then be used to explain away poor response to T4

Until FT3/T3 is recognised as the important thyroid hormone I guess little will change.

[dolphin5]

Amazing! Apart from the lack of mention or consideration of FT3 levels, there seems to be an underlying assumption that, all things being equal, dosing patients according to a nice simple formula should do the job!

There doesn’t seem to be a recognition that we all have our own set point for hormone levels, (and different activity levels etc etc), and there’s no real indication that a person centred approach should be taken.

Listening to the patient seems to be an irrelevance. The authors appear to favour an approach which involves the doctor being an independent investigator, as if the patient were simply a list of numbers and facts rather than a human being (probably of the female variety).

Not that I’m sick to death of the lack of progress in thyroid treatment or anything …… 🧐😖😤😵‍💫

But thank you Diogenes, as always. I wish they would at least listen to you, even if they don’t listen to patients (who, from personal experience, as well as listening to other patients, can make a much better job of it by self-medicating!!!)