Does DHT cross the blood-brain barrier?

  1. Registered User
    galapagos's Avatar
    Join Date
    Aug 2007
    Posts
    30
    Answers
    0

    Does DHT cross the blood-brain barrier?


    I've scoured the internet and can't find anything...anyone know?

  2. Registered User
    ECTOmorph's Avatar
    Join Date
    Mar 2006
    Posts
    378
    Answers
    0


    Quote Originally Posted by galapagos View Post
    I've scoured the internet and can't find anything...anyone know?
    what do u mean?

    dht is the alpha hormone in the brain
  3. Registered User
    galapagos's Avatar
    Join Date
    Aug 2007
    Posts
    30
    Answers
    0


    I mean, I know that testosterone and estrogen are exchanged freely between brain and bloodstream, but does this apply to DHT as well? Does DHT in the brain derive entirely from testosterone that enters from the bloodstream, or can DHT be produced in peripheral tissues and then proceed to enter the brain? This is what I am wondering.
    •   
       

  4. Registered User
    jaydee's Avatar
    Join Date
    Sep 2006
    Posts
    315
    Answers
    0


    Can I ask why your asking? Is it the mental side of things your concerned about like brain fog etc.....or the libido ect....?
  5. Registered User
    galapagos's Avatar
    Join Date
    Aug 2007
    Posts
    30
    Answers
    0


    I ask because I am very interested in figuring out the mechanism by which finasteride might actually cause HPTA shutdown.

    In my own case, all of my other hormones are essentially normal (E2, SHBG, prolactin, etc...), but my testosterone is low (this is 1.5 years after 2.5 years on fin). So, in my case, this is not simply metabolic low T (i.e. high E, high SHBG, high prolactin). I'm trying to elucidate a mechanism by which finasteride could cause shutdown mediated by negative feedback (in essence, similar to anabolic steroid induced hypo).

    Finasteride shuts down 5AR type II (expressed preferentially in peripheral tissues), causing serum T to increase. At the same time 5AR type I is immune to finasteride, and continues to convert T to DHT in the hypothalamus and pituitary.

    Assuming that DHT does not cross the blood-brain barrier, we might then expect that the elevated serum T would enter the hypothalamus/pituitary, in turn causing an increase in DHT. This increase DHT would have strong negative feedback effects on the HPTA, thus potentially leading to shutown.

    This hypothesis is however weakened by two facts: 1) DHT is metabolized in the liver, and thus must permeate the BBB to get there; and 2) the data generally indicate that there is no significant change in LH and FSH during finasteride administration - and thus no real negative feedback (although, interestingly, there was one study that did in fact demonstrate a decrease).

    So basically, if DHT does not cross the blood-brain barrier, or does not cross easily for that matter, it might provide support for a possible mechanism of finasteride-mediated HPTA shutdown.
  6. Registered User
    Hyde12's Avatar
    Stats
    5'9"  200 lbs.
    Join Date
    Nov 2006
    Posts
    1,920
    Answers
    0


    Quote Originally Posted by galapagos View Post
    I ask because I am very interested in figuring out the mechanism by which finasteride might actually cause HPTA shutdown.

    In my own case, all of my other hormones are essentially normal (E2, SHBG, prolactin, etc...), but my testosterone is low (this is 1.5 years after 2.5 years on fin). So, in my case, this is not simply metabolic low T (i.e. high E, high SHBG, high prolactin). I'm trying to elucidate a mechanism by which finasteride could cause shutdown mediated by negative feedback (in essence, similar to anabolic steroid induced hypo).

    Finasteride shuts down 5AR type II (expressed preferentially in peripheral tissues), causing serum T to increase. At the same time 5AR type I is immune to finasteride, and continues to convert T to DHT in the hypothalamus and pituitary.

    Assuming that DHT does not cross the blood-brain barrier, we might then expect that the elevated serum T would enter the hypothalamus/pituitary, in turn causing an increase in DHT. This increase DHT would have strong negative feedback effects on the HPTA, thus potentially leading to shutown.

    This hypothesis is however weakened by two facts: 1) DHT is metabolized in the liver, and thus must permeate the BBB to get there; and 2) the data generally indicate that there is no significant change in LH and FSH during finasteride administration - and thus no real negative feedback (although, interestingly, there was one study that did in fact demonstrate a decrease).

    So basically, if DHT does not cross the blood-brain barrier, or does not cross easily for that matter, it might provide support for a possible mechanism of finasteride-mediated HPTA shutdown.
    interesting
  •   

      
     

Similar Forum Threads

  1. Replies: 4
    Last Post: 11-12-2012, 07:08 PM
  2. How long does it show in the blood?
    By xandelupo in forum Anabolics
    Replies: 8
    Last Post: 08-20-2007, 08:14 PM
  3. Does Clen affect the Prostate?
    By custom in forum Supplements
    Replies: 24
    Last Post: 09-10-2004, 07:32 PM
  4. Does 1-test elevate blood pressure
    By deftone in forum Anabolics
    Replies: 4
    Last Post: 05-02-2003, 10:04 AM
  5. Replies: 5
    Last Post: 04-22-2003, 04:56 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in