Two Questions about SHBG and E2

[zadok]

I have read conflicting things about the levels of SHBG upon application of testosterone. Do SHBG levels go up or down when test levels go up?

Also is there a 'free E2' test, or can you only test for E2?

Zadok

[marianco]

Originally Posted by zadok

I have read conflicting things about the levels of SHBG upon application of testosterone. Do SHBG levels go up or down when test levels go up?

Also is there a 'free E2' test, or can you only test for E2?

Zadok

Sex Hormone Binding Globulin (SHBG) production by the liver depends on the summ effect of promoting and inhibiting factors.

SHBG promoting factors include: estrogens, thyroid hormone, substances which speed up liver production (including several anticonvulsants), liver disease, etc.

SHBG inhibiting factors include: testosterone, DHEA, insulin, DHT, growth hormone, etc.

One test for free estradiol (E2) is a saliva test for estradiol.

[zadok]

Originally Posted by marianco

One test for free estradiol (E2) is a saliva test for estradiol.

Thanks for the reply. So a saliva test for E2 will give free E2? how is this the case, can you explain it a bit more? I am guessing that free E2 follows that same principal as Free Test? Free E2 is that which is not bound by SHBG (and whatever else E2 binds to)

Thanks,

Zadok

[pmgamer18]

Originally Posted by zadok

Thanks for the reply. So a saliva test for E2 will give free E2? how is this the case, can you explain it a bit more? I am guessing that free E2 follows that same principal as Free Test? Free E2 is that which is not bound by SHBG (and whatever else E2 binds to)

Thanks,

Zadok

Never heard of Free E2 or what it will tell one. Not sure what doing a Free E2 test will tell you.

[masterpp]

does that mean that rasing testosterone levels, and conversely lowering estrogen levels, has the effect of lowering shbg

[zadok]

Originally Posted by marianco

Sex Hormone Binding Globulin (SHBG) production by the liver depends on the summ effect of promoting and inhibiting factors.

SHBG promoting factors include: estrogens, thyroid hormone, substances which speed up liver production (including several anticonvulsants), liver disease, etc.

SHBG inhibiting factors include: testosterone, DHEA, insulin, DHT, growth hormone, etc.

One test for free estradiol (E2) is a saliva test for estradiol.

Thanks for the reply,

Couple more questions:

In normal situations what percentage of E2 binds to SHBG, and what else does it bind to?

What substances speed up liver production?

Thanks,

Zadok

[zadok]

bump

[asih.net]

Originally Posted by zadok

Thanks for the reply,

Couple more questions:

In normal situations what percentage of E2 binds to SHBG, and what else does it bind to?

What substances speed up liver production?

Thanks,

Zadok

================================================== =====

In a previous post I detailed some of the relationships of SHBG.


http://forum.mesomorphosis.com/showthread.php?t=134241271

In TRT, keeping everything else equal, the SHBG level will not be affected greatly as long as T levels are kept within the normal range. Elevations above normal, however, will decrease SHBG.


Recent evidence shows that SHBG can participate in signal transduction via its own membrane receptor. In normal men between 40 and 65% of circulating testosterone (T) and between 20 and 40% of circulating estradiol (E2) is bound to SHBG. T and E2 bind to the same binding site on SHBG, but the binding affinity for T is higher than that for E2. Binding of T to SHBG decreases its metabolic clearance rate and its conversion rate to androstenedione. Binding to SHBG also prevents bound hormone from diffusing out of the bloodstream, thereby preventing hormone binding to the intracellular androgen or estrogen receptors. The non-SHBG-bound fraction of hormone is, therefore, considered to be bioactive (free hormone hypothesis).

The concentration of SHBG is significantly correlated with age and anthropometrics. Weight which is often used as a predictor of SHBG concentration is not an independent predictor of SHBG when controlled for BMI and WHR (Waist to Hip).

Just for Fun. Diet & SHBG.

The dietary components that correlate best with SHBG levels are protein and fiber. The lower the protein intake, the higher the concentration of SHBG. This mirrors findings in rabbits and indicates that protein intake can be an important control of SHBG level. The mechanism by which protein intake can be a controlling factor on SHBG concentration is uncertain. One of the major controlling factors on SHBG synthesis is insulin. This intake of protein has been shown to increase insulin levels, and insulin has been shown to reduce SHBG levels. The effect of protein on SHBG could be mediated in part by its effect on insulin, with a low protein intake leading to low insulin levels and release of the inhibition of SHBG synthesis. If this were to be the mechanism by which protein effects SHBG levels, one would expect that carbohydrate (CHO) intake, a stimulus for insulin release, would also effect SHBG levels. There is no significant relationship between CHO intake and SHBG levels. Therefore, it is likely that the relationship of protein intake to SHBG levels involves more than a possible effect on insulin.

Glucocorticoids can increase insulin resistance of peripheral tissues and lead to higher insulin levels. A decrease in glucocorticoid secretion could result in decreased resistance to insulin, lower insulin levels, and, hence, higher sex hormone-binding globulin levels!!

Peace

Mike

[pmgamer18]

So is it true that high E2 can keep Free T down and SHBG up to high. When I had my E2 tested 3 yrs. ago it was 90 and my Free T was in the low end of my labs range. Getting my E2 down to 24 my Free T went up over the top of the range. Was it the E2 taking up the space in the cells that the T could not get to. Is it true that E2 and T look the same to the brain and can't tell the difference in the cells.

[zadok]

Dr Scally,

I have

SHBG: <5nmol/l (17-70)
FT: 50pmol/l (49-145)
TT: 18nmol/l (5.2-22)

E1,E2,E3: I cannot remember the exact results but they are all well within check (low-mid range). However I am still suffering from high E symptoms. No libido, shrunken penis, bloated appearance. Is this because there is now such a high percentage of 'free E2'? I am in a bit of a catch 22 situation because if i take any AI's this lowers E2, but also SHBG, I always feel worse. What can I do? I suspect my SHBG output has been affected by oral steroid abuse.

Zadok

[hackskii]

Would high SHBG bind to test and allow for less free test?

So to a point wouldnt SHBG be better if on the lower end?

[pmgamer18]

Originally Posted by hackskii

Would high SHBG bind to test and allow for less free test?

So to a point wouldnt SHBG be better if on the lower end?

My Dr. says it is not a good test to do SHBG if you can do Free T and yes if Free T is higher SHBG is on the lower side most times.

[zadok]

bump