ExcelMale
Menu
Home
What's new
Latest activity
Forums
New posts
Search forums
What's new
New posts
Latest activity
Videos
Lab Tests
Doctor Finder
Buy Books
About Us
Men’s Health Coaching
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Navigation
Install the app
Install
More options
Contact us
Close Menu
Forums
Testosterone Replacement, Low T, HCG, & Beyond
Testosterone and Men's Health Articles
Testosterone fractions in blood?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="madman" data-source="post: 195909" data-attributes="member: 13851"><p>Key points to keep in mind:</p><p></p><p><strong>*<em><u><strong>In</strong> normal men, only 2% of total testosterone circulates freely in the blood, while 44% is bound to SHBG and 54% to albumin</u>.</em></strong></p><p></p><p><em><strong>*In </strong></em><strong><em>normal, healthy men with an intact hypothalamic-pituitary-testicular axis, <u>an increase in plasma concentrations of SHBG leads to an acute decrease of free testosterone and simultaneous stimulation of testosterone synthesis, persisting until the achievement of normal concentrations</u>.</em></strong></p><p><strong><em></em></strong></p><p><strong><em>*<strong><em><u>About 1.5–2% of serum testosterone is free and is believed to represent bioactive testosterone</u>. Free and protein-bound testosterone and DHT are in equilibrium so that when the free hormone is subtracted from circulation because of entry into the tissue, new testosterone dissociates from albumin and SHBG, a new equilibrium is promptly reached, and the free-hormone concentration in serum remains constant.</em></strong></em></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong></strong></p><p><strong>The new dynamic model (Model F) leads us to reconsider <u>several dogmas related to testosterone’s binding to SHBG and have important physiologic and clinical implications</u>.</strong></p><p><strong></strong></p><p><strong><em>*<u>First, the fraction of circulating testosterone, which is free is substantially greater (2.9 ± 0.4%) than has been generally assumed (%cFTV 1.5 ± 0.4%)</u>.</em></strong></p><p><strong><em></em></strong></p><p><strong><em>*<u>Second, percent FT is not significantly related to total testosterone over a wide range of total testosterone concentrations. However, the percent FT declines as SHBG concentrations increase, although it does not decline as precipitously as predicted by Vermeulen’s model</u>. <u>Due to the allostery between the two binding sites, SHBG is able to regulate FT levels in a much larger dynamic range</u>.</em></strong></p></blockquote><p></p>
[QUOTE="madman, post: 195909, member: 13851"] Key points to keep in mind: [B]*[I][U][B]In[/B] normal men, only 2% of total testosterone circulates freely in the blood, while 44% is bound to SHBG and 54% to albumin[/U].[/I][/B] [I][B]*In [/B][/I][B][I]normal, healthy men with an intact hypothalamic-pituitary-testicular axis, [U]an increase in plasma concentrations of SHBG leads to an acute decrease of free testosterone and simultaneous stimulation of testosterone synthesis, persisting until the achievement of normal concentrations[/U]. *[B][I][U]About 1.5–2% of serum testosterone is free and is believed to represent bioactive testosterone[/U]. Free and protein-bound testosterone and DHT are in equilibrium so that when the free hormone is subtracted from circulation because of entry into the tissue, new testosterone dissociates from albumin and SHBG, a new equilibrium is promptly reached, and the free-hormone concentration in serum remains constant.[/I][/B][/I] The new dynamic model (Model F) leads us to reconsider [U]several dogmas related to testosterone’s binding to SHBG and have important physiologic and clinical implications[/U]. [I]*[U]First, the fraction of circulating testosterone, which is free is substantially greater (2.9 ± 0.4%) than has been generally assumed (%cFTV 1.5 ± 0.4%)[/U]. *[U]Second, percent FT is not significantly related to total testosterone over a wide range of total testosterone concentrations. However, the percent FT declines as SHBG concentrations increase, although it does not decline as precipitously as predicted by Vermeulen’s model[/U]. [U]Due to the allostery between the two binding sites, SHBG is able to regulate FT levels in a much larger dynamic range[/U].[/I][/B] [/QUOTE]
Insert quotes…
Verification
Post reply
Share this page
Facebook
Twitter
Reddit
Pinterest
Tumblr
WhatsApp
Email
Share
Link
Sponsors
Forums
Testosterone Replacement, Low T, HCG, & Beyond
Testosterone and Men's Health Articles
Testosterone fractions in blood?
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top