From:   Holly Jagger <[log in to unmask]>

-When my Cortisol or mineralocorticoid replacements are on the low side,
even slightly, would T4 convert in a different way than it 'should'?

Yes.  Cortisol is necessary to convert T4 to T3.

http://www.chiroweb.com/archives/18/07/03.html
"Adrenal function is critical in the conversion of T4 to T3, which is 10
times more active than T4, in peripheral tissues. This conversion of T4 to T3 is
influenced by adrenal cortisol, iron, selenium, B12 and magnesium. Too much
cortisol in the system can induce a conversion of T4 to an improper form of T3
called reverse T3 (rT3), as shown in Figure 2."
**************************

My wife has high cortisol, probably the reason she does well on timed release
T3.  Any T4 in her system, she turns into inactive rT3.  If you read the
literature for Cortef or Prednisone, it says that it affects thyroid tests and T3
conversion.  I'm on Cortef (hydrocortisone) but don't feel as well on T3
alone.

I think with low cortisol, you simply don't convert the T4 to T3, it gets
excreted.

I don't think the T3 levels on the labs will be off because you are on a
natural replacement dosage of cortisol, not high levels.  On the other hand, T3
testing is known as being a little inaccurate anyways.  How you feel is more
important.

Dr. Michael on this list is good with the combination of thyroid and adrenal
replacement.  An excellent book about the subject is "The Great Thyroid
Scandal and How to Survive It" by Dr. Barry Durrant-Peatfield.  He found that
sometimes if people were given hydrocortisone, their thyroid symptoms went away,
sometimes they didn't need thyroid treatment and the adrenal need was only
temporary.  Regardless, the the thyroid treatment typically worked better if h
ydrocortisone was started first.

Skipper




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