What signals the hypothalamus to stop endogenous testosterone production during TRT?

**wenis piggler** · 03-12-2009, 09:06 AM

What signals the hypothalamus to shutdown endogenous testosterone production when on TRT? Is it the increased estrogen alone, via aromatase, or is it the increased exogenous testosterone (TRT) itself, or both or something else? If it is only the increased estrogen that shuts-down the endogenous testosterone, then wouldn't endogenous testosterone start working again if estrogen is lowered, via an AI, while on TRT?

In the absence of estrogen, via an AI, would endogenous testosterone production start up again, even while one were still on exogenous testosterone (TRT)?

Will either estrogen or exogenous testosterone (TRT) suppress/shutdown the endogenous testosterone production?

Sorry for the redundant questions, but I had a hard time posing the question; therefore, I took the "shotgun approach."

Thanks

P.S. Any links or articles would be great!!

**MuscleScience** · 03-12-2009, 09:20 AM

High levels of testosterone ,

**lex57** · 03-12-2009, 09:23 AM

there is a thread where a member named "musclescience" has a thread called ask me a question or something to that effect. it would be a good question there i will try to link it. my opinion would be the increase of exogenous test would trigger the feedback mechanism to stop endogenous test production but i am no expert. very novice when it come to physiology of the human body, but i know a lil bit.
Ask the Exercise Scientist

**lex57** · 03-12-2009, 09:24 AM

oh man is that creepy!!!!!!!!!!!!!!!!!!!!!!!!! holy shit! what are the f'ing odds on that?

**wenis piggler** · 03-12-2009, 10:03 AM

Originally Posted by MuscleScience

High levels of testosterone,

Sorry. I just just posted the same question on your thread, Lex57 gave me your link.

Estrogen plays no role? I thought estrogen is at least one of the signals that will shutdown the endogenous test production, but exogenous test will also shut it down as well?

**wenis piggler** · 03-12-2009, 10:05 AM

Originally Posted by lex57

there is a thread where a member named "musclescience" has a thread called ask me a question or something to that effect. it would be a good question there i will try to link it. my opinion would be the increase of exogenous test would trigger the feedback mechanism to stop endogenous test production but i am no expert. very novice when it come to physiology of the human body, but i know a lil bit.
Ask the Exercise Scientist

Thanks! I left the question on his thread, after I realized he answered it on my thread.

**MuscleScience** · 03-12-2009, 04:21 PM

Originally Posted by wenis piggler

Thanks! I left the question on his thread, after I realized he answered it on my thread.

I just saw your question, and posted a reply for two basically...LOL

You are correct estrogen, specifically estradiol will inhibit LH production by the hypothalamus, is the most responsible.

**wenis piggler** · 03-12-2009, 05:51 PM

Originally Posted by MuscleScience

I just saw your question, and posted a reply for two basically...LOL

You are correct estrogen, specifically estradiol will inhibit LH production by the hypothalamus, is the most responsible.

Is it e2, testosterone (exogenous), or both that suppress the hypothalamus? I have heard that it is e2 that suppresses it, but if you use an AI and therefore have low/no e2, then is it the test (exogenous) that is suppressing your natural production?