Thyrotropin Plays Dual Role In Metabolism And Sensing Seasonal Changes Without Confusion

[helvella]

It is some time now since I found out that not all TSH is the same. TSH is attached to sugar molecules - and these can vary. From the first realisation that this was the case, I assumed (without any evidence at all!) that this was significant and important. That which sugar molecule is attached could affect what the TSH does.

I don't pretend to know or understand what that significance is, nor how important it might be, just that it can't simply be brushed under the carpet.

So my delight and astonishment at reading the article below (you will have to follow the link to read it all). If it proves correct, then thyroid issues yet again seem to be absolutely fundamental to all animals in yet more ways.

Thyroid Hormone Thyrotropin Plays Dual Role In Metabolism And Sensing Seasonal Changes Without Confusion

An international collaborative study between Japanese and American scientists has revealed how a single hormone multi-tasks without muddling up its functions. The hormone in question is thyrotropin, the thyroid-stimulating hormone (TSH) that manages to activate seasonal sensing and regulate metabolism without any confusion.

TSH is secreted from the pituitary glands from two parts. TSH secreted from the front of the pituitary gland, pars distalis, goes on to stimulate the thyroid gland to secrete the hormone thyroxine, which plays a primary role in the regulation of metabolism.

TSH is also secreted from the stalk of the pituitary gland, pars tuberalis, and is known to act on the hypothalamus. While both proteins have the same structure, the exact role of TSH being secreted from the pars tuberalis was unknown until the Japanese team, led by Professor Takashi Yoshimura, discovered it acts as a novel spring-calling hormone, sending information and controlling how the body reacts to seasonal changes.

If that was interesting, read the rest of the article here:

medicaldaily.com/thyroid-ho...

And, at present, the full paper is available here:

cell.com/cell-reports/pdf/S...

Full text available on-line and without charge:

cell.com/cell-reports/fullt...

Rod

[PR4NOW]

Rod, great find, did you notice Dr. Refetoff is one of the authors? I had a devil of a time downloading.

This link gives the page to download either the regular or extended version. The extended kept freezing up my computer but the regular did not, no idea why. There is also a .ppt for the images. When you consider this along with the article you posted on 'Bitter Taste Receptors' it just shows how little we really understand the total system. PR

cell.com/cell-reports/abstr...

PS I still think that the TSH isoforms have something to do with the circadian rhythm at night of TSH and T3.

[diogenes Remembering]

Two things to say. First yet another complication in the interplay of pituitary, thyroid and tissues through TSH modification. Second a thank you from me to HU for alerting me quite often to articles of interest that I hadn't then encountered. Quite a few have added significantly to my archive and ideas emanating from the information. Eg this article's findings will enter into our review in progress.

[PR4NOW in reply to diogenes]

Diogenes, is your other paper regarding TSH and extra thyroidal conversion still in the review process before publishing? PR

[diogenes Remembering in reply to PR4NOW]

Yes,I'm sorry to say. It is now 2 months since submission. A disgraceful delay, by which a conspiracist might think something sinister is going on. But it's just the usual bumbledom of inadequates I'm afraid. If this doesn't work then we bite the bullet and go to an open access journal who are very much more on the ball, but you certainly pay for the privilege. But it will speed up things.

[Winegum2]

Really interesting! For me particularly as in September I asked for a printout of my BTs for the first time. I was quite interested to find that it was the third September in a row that I had felt unwell enough to go to the Dr and get a range of blood tests. This made me suspect that Autumn was somehow having an effect on my thyroid.

I assume that the TSH test doesn't differentiate between the 2 types of TSH which have different functions. This is another reason why treating the TSH test as God is a misnomer.

[helvella in reply to Winegum2]

From my little area of ignorance, I have no idea how the two forms of TSH affect the TSH tests. If anyone does have any solid information, it would be much appreciated.

What we do know is that antibodies to TSH itself can cause TSH tests to appear far higher than they should. At least some TSH tests use techniques that prevent this interference from happening but I think some TSH tests are still affected. I cannot say whether any are in use in the UK.

Rod

[diogenes Remembering in reply to helvella]

It all depends on the exact quality and recognition of the outside sugar-protein topography of the TSH molecules. This simply means the exact shape and orientation of the various protein and sugar molecules. A monoclonal antibody is raised against a particular form of TSH and then used as a testbed to make an assay. But the various TSH tests in existence will use different sources of monoclonals. These will have different recognitions of different TSH's and this may lead to distortions in measurement. If for example, TSH form 1 was less well recognized than form 2 in one test, whereas both were equally recognized in another, then the first test could read low in certain circumstances where form 1 predominated, compared with the other test. TSH diversity from such causes is far more of a headache for test development than simple T4 and T3.

[helvella in reply to diogenes]

Thank you, diogenes.