Any Good Visualisations Of The Iodine Dependent Thyroxine Production Pathway? (As Explanation For People Asking About The Fukushima Nuclear Plant Disaster)

Question

[Chris Evelo]

I saw a few question people on twitter asking why the Japanese government might want to distribute iodine tablets to protect against radiation from the damaged Fukushima nuclear plants. Part of the answer to that question is that iodine (both radioactive and normal) are actively concentrated in the thyroid because of thyroxine production. The active thyroid hormone products contain either 3 triiodothyronine (T3) or 4 thyroxine (T4) iodine atoms.

It would be good to have an easy to understand visualization of the thyroxine production pathway to explain this better. If that would also include the relevant genes active in transport and synthesis, it could furthermore be a start to understand or evaluate risks better. It could for instance help to ask the question whether Japanese or older people would be relatively (in)sensitive depending on the relative expression of these genes or possible variants in them.

Currently we have the thyroxine production pathway as part of the Reactome pathway "Metabolism of amino acids and derivatives" that is also available for community curation as WikiPathways pathway WP1847. But that does not really give a clear overview of this specific process. Does anyone know of a better, more explanatory visualization of that same pathway which could be used as the start of a more intuitive pathway at WikiPathways?

Thanks to help from some Biostar users we now have a start of a real pathway for thyroxine production, it still needs a lot of work, but there is some interesting info in it.

[Darked89]

Pure physiology 0.02$ worth hint. Incorporation of iodine plus production of thyroxine is strongly influenced by diet. I would think that people in coastal Japan have a high iodine intake (think sea fish) and possibly high intake of raw(?) cruciferous vegetables (wasabi, daikon, etc).

This may swamp any genetic effects in the pathway itself.

[Chris Evelo]

+1 for the diet. But do you think thyroxine production is relevant in general and especially when countering radioactive iodine exposure is involved? Or is it just the iodide? And can you really eat significant amounts of wasabi? I always thought that is more a spice than a vegetable.

Answer 1

[Andra Waagmeester]

It is not a visualization but the WHO provides a very informative guideline at http://www.who.int/ionizing_radiation/pub_meet/Iodine_Prophylaxis_guide.pdf. This document also has quite some references, of which http://www3.cancer.gov/intra/dce-old/pdfs/tceer.pdf is just one example.

I lack the time to create a full pathway on WikiPathways, but I have created a stub http://www.wikipathways.org//index.php?title=Pathway:WP1981, so maybe you and the community can add relevant parts.

[Chris Evelo]

Thanks Andra. I added some core hormones, metabolites and enzymes to that pathway, but it still really is a stub, not showing the real interactions.

Answer 2

[Larry_Parnell]

I'd take a look at the Human Serum Metabolome database. There are entries for iodine and thyroxine. Unfortunately, there are no pathway data links from the iodine MetaboloCard entry, but thyroxine has a few different pathway links including the HSMD's own.