OT General Question - sex hormone-binding globulin

[Desmo996]

I know that this protein binds with Testosterone, DHT, and Estradiol, but what exactly is its purpose? What does it do once it is bound? I can't seem to find and reason for this protein to exist at all, other then to make these hormones biologically inactive.

 

[zaarel2]

a little stolen blurb

Heres a bit of a stolen blurb along with its originators credit.

There is some research showing that SHBG is more than just a carrier for test. An SHBG receptor (SHBG-R) has recently been identified in the brain and prostate and sheds some light on the observation that estrogen can exacerbate prostate cancer.

People think that when SHBG binds to SHBG-R, the SHBG/SHBG-R system works as an additional control mechanism which inhibits or amplifies the effects of DHT and estradiol in cells. In the prostate, it has been suggested that the estradiol-activated SHBG/SHBG-R complex cross-talks with the androgen receptor, and is able to activate AR even in the absence of DHT. In the breast, research has shown that the SHBG/SHBG-R complex can antagonize the proliferative effect of estrogen on breast cancer. So SHBG has an androgenic/anti-estrogenic effect in the prostate and breast. Does it interact with estrogen to activate the androgen receptor in skeletal muscle? I have not seen any research on this.

 

[SWALE]

Since estrogen generally increases SHBG levels, this effect would help counteract same, and add some balance.