SHBG: Sex Hormone Binding Globulin Posted on 10 Apr 20:57 , 0 comments
I do not regulate my SHBG levels directly, only indirectly.[/caption]
By Todd Lee M.D.
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Sex Hormone Binding Globulin
Sex hormone-binding globulin, or SHBG, is a controversial topic. A lot of people just load up on Proviron to competitively inhibit SHBG without knowing what it does.
So Let's Go Over The Basics
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Clearly a decrease in SHBG results in a Higher Free testosterone and bioavailable testosterone, seemingly a good thing.[/caption]
SHBG binds sex hormones. DHT > testosterone > estradiol. So the more SHBG, the less free testosterone floating around. Free testosterone tends to be broken down quickly. When free levels go down, the concentration of free-bound decreases, so basic chemistry results in the currently bound unbinding to regenerate the free pool. It’s not necessarily bad; without it you wouldn't have a readily available supply of free testosterone.
Creation and Regulation of SHBG
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Sex hormones influence the development of all these tissue types. Thus a carrier of these hormones absence could influence the maintenance of all these organs relying on these tissue types[/caption]
SHBG is made in the liver and is down-regulated by androgens, like testosterone and DHT, as well as growth hormone, IGF-1 and Insulin. Basically, everything a bodybuilder would take to build muscle will cause SHBG to go down.
Estrogens, thyroxine (T4), and rare drugs cause SHBG to go up. So not only do women make more estrogen and less testosterone, but the estrogen causes SHBG to go up which binds the free test more in women making the ratio of free test:estradiol even lower.
SHBG is a Hormone?
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SHBG as a carrier molecule[/caption]
What people may not know about SHBG is that on certain organs, which typically have receptors for sex hormones, there is a specific SHBG receptor! In order for SHBG to bind to its receptor, it can't be bound to any hormone. But after it binds to its receptor, if it binds to a hormone like estradiol or DHT, it alters the way that specific cell responds to the normal hormone receptor complex. The results are counterintuitive and not well understood. For instance, it’s obvious the prostate would be activated by DHT activity right? But the SHBG-receptor/DHT complex DEACTIVATES healthy prostate cells but ACTIVATES prostate cancer cells. It actually gets a lot more complicated than that. Inactive metabolites of the hormones may have active binding and functioning when bound to the SHBG/SHBG-receptor complex.
So the SHBG molecule is a functional hormone, not just a carrier molecule, and should probably be left alone since we don't completely know what it does.
Disclaimer
Nothing in this article or on this site should be considered medical advice or as an endorsement to violate any law of the country in which you reside. The information given is for fun and entertainment purposes only. All claims are 100% dependent upon proper diet and exercise. Please consult a medical practitioner prior to any diet and exercise program.