Does Anyone Have Any Experience Of/ Knowledge About SSKI vs. Lugol's, Please?

[alicec]

Is there a reference you can point me towards to look at how the NIS only transport iodide, please? Also, which enzymes and what are their components? I ask because occasionally, it is possible to reactivate "broken" enzymes by supplementing their base component, e.g., as with selenium for 5'-deiodinase. What have you seen that states NIS don't/can't use iodine?

That is the nature of the transporter - it transports one iodide ion and two sodium ions into the cell. It is coupled to the sodium-potassium ATPase (ie energy is required to drive the process). Here is the wikipedia entry. Here is a recent review.

There is another transporter pendrin which is also specific for iodide. These are the only known iodine transporters.

The enzyme thyroid peroxidase (TPO) catalyses the oxidation of iodide to iodine which immediately reacts with tyrosine residues in thyroglobulin forming protein bound thyroid hormones which are later released.

The oxidising agent is hydrogen peroxide which is generated by members of the NADPH oxidase family, the dual oxidase enzymes DUOX1 and DUOX 2. Another family member NOX4 seems to play some role also.

Hydrogen peroxide is not the sort of thing you want hanging around in the cell so this reaction is tightly controlled and the two enzymes tightly coupled.

Iodine doesn't hang around either - it is used as it is generated.

Here is a review.

In the breast, substitute lactoperoxidase for TPO.

Edit to add.

TPO and LPO use calcium and haem b as cofactors.

DUOX uses calcium and NADPH (hence niacin) and is a flavoprotein (B2 requirement).

 

[alicec]

I'm aware that iodide is absorbed in the duodenum. I was under the impression that iodine and iodide could be absorbed from the stomach and the gut. What have you seen that supports virtually all iodine being converted to iodide, iodide only being absorbed from the gut, and NIS only using iodide? Is it accepted physiology, or is there research to support it? -

Research shows that NIS is abundantly expressed on enterocytes in the small intestine and that this is the mechanism of uptake of iodine (in the form of iodide) into the cell. Here is a recent study.

NIS is present in the stomach but it transports in the opposite direction - ie iodide is secreted into the stomach (and is presumably reabsorbed in the small intestine).

It is possible that there might be other anion exchangers (unknown at this stage) which could transport iodide.

There are no known mechanisms for transporting iodine (as opposed to iodide) into the cell. I recall reading in an in vitro study (on breast cancer cells) that some kind of facillitated diffusion might be involved in direct iodine uptake. This is possible but is purely speculative.

In any case, a variety of older studies showed that the vast majority of iodine taken up into the body is in the form of iodide. Other routes are indeed possible but they would appear to be a minor part of iodine metabolism and at this stage the mechanism is unknown.

 

[alicec]

re: I2 (iodine) action seperate from I~ (iodide) action.

Not the ref I was looking for, but -
http://iodineresearch.com/files/aceves_2005_iodine_gatekeeper_mammary_gland.pdf

I had already read a later review from these same authors. I figured since they were advocating a special and different role for iodine they should give the best available references.

As I've said already, I found the evidence to be very thin. The most compelling is the in vivo studies which show different effects from different iodine sources. These are certainly suggestive it is just a pity that there has been no real follow-up from a few very old studies. We still know nothing about what these observations really mean nor what mechanism is behind them.

 

[Jigsaw]

@alicec,

Speaking of iodide, is it safe to use USP/BP/EP grade KI instead of ACS grade to make SSKI?

 

[alicec]

@alicec,

Speaking of iodide, is it safe to use USP/BP/EP grade KI instead of ACS grade to make SSKI?

Yes they all indicate high purity analytical grade chemicals.

I have edited the post on the different enzymes to add cofactor info.

 

[Jigsaw]

Yes they all indicate high purity analytical grade chemicals.

I have edited the post on the different enzymes to add cofactor info.

Thanks.

So BP/EP/USP KIs all safe to ingest, then?

Does the KI used in Lugol's have to be ACS/Reagent grade, or doesn't it matter if it's the same BP/EP/USP grade that you've said is fine for SSKI?

Just seen one KI stating ACS purity but listing various other metals etc as 5ppm, which seems high to me. Thinking of how it will react with the I2 component.

 

[alicec]

The designations refer to things certified by different agencies - British, European and US pharmacopaeia - to be safe for medicinal or cosmetic use.

ACS is American Chemical Society and the certification is used more generally for high purity laboratory chemicals.

For your purposes all are fine.

 

[Jigsaw]

The designations refer to things certified by different agencies - British, European and US pharmacopaeia - to be safe for medicinal or cosmetic use.

ACS is American Chemical Society and the certification is used more generally for high purity laboratory chemicals.

For your purposes all are fine.

Thanks @alicec