SHBG can act as a marker for tissue levels of T3

[pattismith]

SHBG: Broadening the Scope of Hypothyroid Testing
by Holtorf Medical Group

extract:


"The role of SHBG is to protect regulate, and transport sex hormones, estrogen and testosterone. Produced primarily in the liver, SHBG binds to the hormones and shuttles them to tissues in body. When bound to SHBG the hormone, i.e. estrogen, it isn’t “free” or available. It’s important for the body to maintain the right amount of available estrogen, relative to the bound estrogen, as well as to the other hormones. Balance and synchronicity are key. An imbalance, along with low SHBG levels is frequently found in conditions with low thyroid transport (previously listed).

SHBG production responds to thyroid and estrogen hormones, which is why it’s considered to be a good indicator of thyroid tissue levels. In general it is a better marker for women than men. If estrogen levels are satisfactory, SHBG can act as a marker for tissue levels of T3 unless a woman is taking oral estrogen hormone replacement therapy (HRT).
In this case, SHBG levels will elevate in response to increased estrogen levels in the liver caused by metabolizing the HRT. SHBG testing would therefore not be a true indicator, unless transdermal patches or creams are used. Simply put, SHBG levels impact estrogen and estrogen affects the thyroid. Thyroid hormones also affect SHBG levels by increasing its production and often diminishing free estrogen. Confused? Here is a gauge:

SHBG for women with adequate estrogen levels should be above 70 nmol/L, and men above 25 nmol/L. For those using thyroid replacement and are below these SHBG levels, it can signify ineffective treatment. SHBG levels are expected to increase when thyroid hormone medications are implemented."


https://www.holtorfmed.com/shbg-broadening-the-scope-of-hypothyroid-testing/

 

[drob31]

My SHBG is way too high, and thyroid is either subclinically low to low normal.

 

[pattismith]

My SHBG is way too high, and thyroid is either subclinically low to low normal.

well, are you a man?

it seems that this marker is more suitable for women than man, and only if estrogen levels are ok, and that no estrogen pills are taken:

"SHBG has both enhancing and inhibiting hormonal influences.
It decreases with high levels of insulin, growth hormone, insulin-like growth factor 1 (IGF-1), androgens, prolactin and transcortin.
High estrogen and thyroxine cause it to increase."

 

[Nine lives]

This thinking was the reason I spaced my natural thyroid AM, 2pm and 8 PM. SHBG fell from 195/175 to 115. I still want it lower so that my free testosterone can rise. 70 would be nice. I am sure for me raising free testosterone will help me feel better.

 

[Judee]

I found out recently after requesting all my records from one of my doctor's offices that my SHBG levels have been low for years. (I'm female and have read since that low SHBG in females can signal diabetes later on so it had me worried.)
He always gave me that test along with others and I'm upset because he never went over those results with me.

Anyway, since Christmas I weaned myself off some of the things he had me on -- low dose DHEA, Iodine, and a second thyroid hormone, waited and then went for the test again on my own. Whew!! It came back normal, still on the low end but back in range and I feel a tiny bit better.

Plus, my eyelashes are growing back now. My thyroid tests were always in the low end of the normal range using TSH (I know not the only one to use). Now my TSH is mid-range but again, I feel a little better. Plus, I had stopped having a lot of hypoglycemic episodes--at least until recently when an eye doctor put me on steroid drops.

 

[Learner1]

@pattismith This is interesting, but confusing.

Last time my SHBG was measured, it was 40, far below the recommended level in the article. I am on very low levels of HRT with estriol/testosterone cream and oral bioidentocal progesterone, plus DHEA and pregnenolone. And hydrocortisone. Does any of this matter?

My TSH is always .006, rT3 is low, FT3 and FT4 are midrange, and thyroglobulin antibodies are high.

I feel fine...

But, according to the article, my SHBG should be over 75, and he only cares about anti-TPO antibodies, not thyroglobulin. And most docs freak at my suppressed TSH...

Is there a problem here? And if so, what do I do?

 

[pattismith]

@Learner1 , you know I'm not an expert! Did you checked the SHBG inhibitors in your blood?

"SHBG decreases with high levels of insulin, growth hormone, insulin-like growth factor 1 (IGF-1), androgens, prolactin and transcortin.

What I noticed is that since I started T3 suplementation, my symptoms of estrogen excess have stopped suddenly (breast tenderness mainly)...so I suppose that my SHBG has increased quickly, binding to my estrogens, which decrease their effects.

if you have anti-thyroglobulin auto-antibodies, it may be that you could have anti T3 anti T4 antibodies that can interfer with T3 and T4 dosages, is your titer very high?

 

[Learner1]

@Learner1 , you know I'm not an expert! Did you checked the SHBG inhibitors in your blood?

Thanks. How would I do that?

What I noticed is that since I started T3 suplementation, my symptoms of estrogen excess have stopped suddenly (breast tenderness mainly)...so I suppose that my SHBG has increased quickly, binding to my estrogens, which decrease their effects.

I got stage 3 uterine cancer on T3 only supplementation with plenty of estrogen excess, so I'm not sure that worked for me.

Currently, I use tiny amounts of HRT to feel.ok, but avoid risk. Pregnenolonr shoots my estradiol through the roof. I'll have my doc measure SHBG again, but suspect it would be low.

if you have anti-thyroglobulin auto-antibodies, it may be that you could have anti T3 anti T4 antibodies that can interfer with T3 and T4 dosages, is your titer very high?

Thyroglobulin Antibody 31.1 IU/mL (0.0-0.9 reference range)

I'm on 137mcg T4 and 50mcg T3, which is high, but if I drop it lower, I don't function. I've never gotten a decent explanation of how thyroglonulin antibodies affect dosing.

Thank you