How Steroid Receptors work?

Ok Bros. Here is the problem I am having. We all know how steroid receptors work to give the anabolic and anticatbolic results. We have seen that famous steroid model, with the steroid binding to a receptor, transfering to the nucleus of the cell and increasing mRNA transcription and thus all the effects associated with steroids. My question is this and is fairly rudametary or it may be profound, lets see with your responses. Our bodies have steroid receptors for the natural steroids our bodies make. Test, DHT, estrogen, progesterone, etc. This makes sense. Ok, Here is the million dollar question that is bugging me. So when someone takes Fina, D-bol, Winny, or whichever syntetic, why is the end result not the same as Test or DHT. Aren't these steroids suppost to be stimulating the same steroid receptors? I cannot imagine we have Fina receptors or D-bol receptors that produce the subtle changes we desire. In fact, I know we don't. I can understand the structure changes for increasing potency, long acting, stability for first pass oral use, but not the big diferences in weight gain, muscle mass, muscle hardness, cutting, qualitative vs. quantitative. How is this happening? So are the syntetics stimulating receptors we have not yet discovered? Is the test receptor being modified and interm producing different proteins than it normaly would not? Or is it to the degree the syntetics have crossover effect with progest, estrogen receptors that give us the illusion that it has a different effect? This is becoming to sound like a thesis question for Biochem, but I think it is important one for all of us. I know there are some briallant folks out there in AR; Doctors, nutritionist, and I know the bros out there in AR land know more about this than they credit for. What dah all think? Am I the only one who's thinking to hard, or maybe the anti-e's are getting to my head. :rolleyes: :D

Good question (AR has some really good threads going right now)... :thumbsup:

Basically the medical world started to alter the testosterone molecule to make the perfect anabolic steroid soon after the Germans first isolated testosterone in the early 20th century. The goal: a compound that gives all the anabolic power with low androgenic side effects - ultimatley being all anabolic and no androgenic.

Testosterone (w/no ester):

http://chemacx.cambridgesoft.com/che...185&height=130

Nandrolone (w/no ester):

http://chemacx.cambridgesoft.com/che...185&height=130

Nandrolone was altered at the 19-Nor position (look for the alteration in the above pics) which gave it a more anabolic (building) powers and less androgenic - with no estrogen aromatization.

There have been a lot of different attempts at producing anabolic steroids by altering testosterone to effect different androgen receptors in the body and produce the desired effects.

For comparison here is what Winstrol looks like:

http://chemacx.cambridgesoft.com/che...277&height=195

They all use testosterone as a base compund with minor changes in its structure to improve it's anabolic effects. You can see the 17A modification on the upper right of this compound which makes it an orally available anabolic-androgenic steroid. Esterfied steroids would have an a chain located at 17B... like this:

Testosterone Enanthate:

http://chemacx.cambridgesoft.com/che...185&height=130

I am glad I am not the only one who finds the pharamcology fascinating. Thanks for the response Warriar, but what I want to know how does each AS cause a certain particular effect in the body. Are these compounds all binding to the same Test receptor or does my theory have any merit that we have yet to discover new receptors.

the answer is... i dont think anyone knows. for example, estrogen replacement therapy uses estrogens from mare urine, which contains nine different types of estrogens. this has less negative effects and more positive effects than just taking one type of estrogen. what difference these estrogens make is unknown and the only reason we know they are better is from peoples experience with taking them. this is true for many other hormones-molecules in the body, they have many physiological actions, but we know of none, or just a few. if more research were focused on hormones in the body there would definitely be more answers, but as it stands it may be years before anyone knows.
-hope this helps

Well for a short answer that is not in great depth particular steroids have different responses due to the way they exact their influence on the body. How easily they bind to a receptor, how long they bind to the receptor, and how much they're action is in response to a receptor can differ greatly with different AAS. For instance Trenbelone has a very high receptor affinity, almost all of winstrol's influence is through the receptor, Testesterone has effects on the body completely outside of its reaction to the receptor.