Aromasin and the AR

pistonpump

pistonpump

Banned
I was wondering if anyone had more info on aromasins binding to the androgen receptor. I would like to know how much it will compete with other androgens...Ok, it is steroidal aromatase inhibitor but what exactly does steroidal mean? I know that it doesnt have a rebound effect and shuts down aromatase but does this mean it does it through the AR? Stupid question maybe but just would like some clarifacation please. Gonna do a test/deca cycle here soon.
 
pistonpump; said:
I was wondering if anyone had more info on aromasins binding to the androgen receptor. I would like to know how much it will compete with other androgens...Ok, it is steroidal aromatase inhibitor but what exactly does steroidal mean? I know that it doesnt have a rebound effect and shuts down aromatase but does this mean it does it through the AR? Stupid question maybe but just would like some clarifacation please. Gonna do a test/deca cycle here soon.
Click to expand...
As far as I recall, Armoasin, a third-generation aromatase inhibitor works through an estrogen pathway. More specifically, Aromasin helps stop the production of estrogen, whereas, Tamoxifen, for instance, works by preventing estrogen from attaching to receptors. I am not aware that Aromasin works via androgen receptors.
 
Exemestane is an interesting one, it permanently binds to Aromatase Enzyme while raising testosterone and IGF-1.

Steroidal refers to anything that acts upon sex organs/functions.
 
Ziricote said:
Exemestane is an interesting one, it permanently binds to Aromatase Enzyme while raising testosterone and IGF-1.

Steroidal refers to anything that acts upon sex organs/functions.
Click to expand...

Okay, so steroidal just refers to sex organs/functions....got it.


I have heard that sterodial AI's lessen the effect of steroids through other pathways besides estrogen reduction...the AR for example....was just wondering if it was true.

I have always like aromasin's profile because you have less likely estrogen rebound and it has a positive effect on IGF levels over other AIs. So ideally i was going to run this with a long injectable cycle because i am prone to estrogenic sides and would rather keep it away.
 
after the Hemodraulix review/test.... Its still up in the air tho because its a long one you know...im sure you guys dont want me testing youre product while im on cycle do you?
 
No, that would be counter-productive considering the insane pumps you are going to get from the Deca/Test cycle. But, I'm sure if you atleast used Hemo-X for 2 weeks before staring your cycle you can honestly give a thorough review.

Regardless Bro, Good Luck!
 
Thanks matt.

Im just waiting for this Hemo anxiously! I have been off of any NO product for about a month now too...





Would anyone happen to know if Aromasin would have any anabolic activity like what people report with Formestane??? They are both steroidal AIs...
 
Ok Aromasin does'nt increase IGF-1 here is a study to prove it, read the results and you'll see a decrease in IGF-1 but also a decrease in IGFBP-3 so they kinda cancel out each other cause more free IGF-1 but less overall so there. Thats at 25mg and at 50mg there is no effect either way which is wierd but thats what they found in males mind you NOT FEMALES!!! Everyone can stop saying it increases IGF-1 by 15-20% show me the studies!!!:clean:

Invalid Link Removed
 
Steroidal refers to its structure. Aromasin itself has very low (almost no) binding to the androgen receptor. A metabolite of exemestane, 17-hydroxyexemestane has significant androgen receptor binding.

1: Mol Cancer Ther. 2007 Nov;6(11):2817-27. Epub 2007 Nov 7.Related Articles, Links
Exemestane's 17-hydroxylated metabolite exerts biological effects as an androgen.

Ariazi EA, Leitão A, Oprea TI, Chen B, Louis T, Bertucci AM, Sharma CG, Gill SD, Kim HR, Shupp HA, Pyle JR, Madrack A, Donato AL, Cheng D, Paige JR, Jordan VC.

Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.

Aromatase inhibitors (AI) are being evaluated as long-term adjuvant therapies and chemopreventives in breast cancer. However, there are concerns about bone mineral density loss in an estrogen-free environment. Unlike nonsteroidal AIs, the steroidal AI exemestane may exert beneficial effects on bone through its primary metabolite 17-hydroexemestane. We investigated 17-hydroexemestane and observed it bound estrogen receptor alpha (ERalpha) very weakly and androgen receptor (AR) strongly. Next, we evaluated 17-hydroexemestane in MCF-7 and T47D breast cancer cells and attributed dependency of its effects on ER or AR using the antiestrogen fulvestrant or the antiandrogen bicalutamide. 17-Hydroexemestane induced proliferation, stimulated cell cycle progression and regulated transcription at high sub-micromolar and micromolar concentrations through ER in both cell lines, but through AR at low nanomolar concentrations selectively in T47D cells. Responses of each cell type to high and low concentrations of the non-aromatizable synthetic androgen R1881 paralleled those of 17-hydroexemestane. 17-Hydroexemestane down-regulated ERalpha protein levels at high concentrations in a cell type-specific manner similarly as 17beta-estradiol, and increased AR protein accumulation at low concentrations in both cell types similarly as R1881. Computer docking indicated that the 17beta-OH group of 17-hydroexemestane relative to the 17-keto group of exemestane contributed significantly more intermolecular interaction energy toward binding AR than ERalpha. Molecular modeling also indicated that 17-hydroexemestane interacted with ERalpha and AR through selective recognition motifs employed by 17beta-estradiol and R1881, respectively. We conclude that 17-hydroexemestane exerts biological effects as an androgen. These results may have important implications for long-term maintenance of patients with AIs.

PMID: 17989318 [PubMed - indexed for MEDLINE]
 
pistonpump said:
you answered my question pretty dead on but just curious does 17-hydroexemestane have any anabolic effects on muscle?
Click to expand...

No data available on that. Since the binding affinity is less than test it would likely act as a partial agonist and probably nogt be very anabolic.
 
pistonpump said:
what are your thoughts on exemestane compared to other AIs out there? do you feel it is superior?
Click to expand...

Most of the AIs on the market are very effective (in most cases >90%) at reducing estrogen levels. Of course the suicidal nature of steroidal AIs suggest greater potency. However, my gut feeling is that when you reduce estrogens that severely that the body compensates by increasing sensitivity somehow.
 
sethroberts said:
Most of the AIs on the market are very effective (in most cases >90%) at reducing estrogen levels. Of course the suicidal nature of steroidal AIs suggest greater potency. However, my gut feeling is that when you reduce estrogens that severely that the body compensates by increasing sensitivity somehow.
Click to expand...

I've heard this too. Is there any way to avoid this? Or to bring the "upregulation" back down after use?

All my pubmed searches have lead me no where in this regard.

EDIT: Recent findings show me that Exemestane doesn't increase sensitivity like the other AI's (even ATD, which I have been told is partly competitive which is why many get rebound)
 
Last edited:
You must log in or register to reply here.
Back
Top