Very simply, there is no such thing as a simple anabolic receptor. Any receptor, including the anabolic receptor, has multiple sub-receptors and co-factors. Tren binds strongly to the clumpy object called the anabolic receptor. Nandrolone binds differently, but still to the anabolic receptor. The proof of this is in looking at the microscopic "soup" released in the cell when the anabolic receptor is bound. When different anabolics bind to the anabolic receptor, different flavors of "soups", with different ratios of second messengers, mRNAs, etc, are released. Organisms are not so black-and-white, all-or-nothing, in their response. A receptor is like a board with 50 switches, any swipe of the hand which hits a few switches will basically "turn the lights on", but the lights may be dimmer or brighter, blue or red tinged in color, etc.
Interestingly, as I posted elsewhere recently, new research shows that dbol and winny, which were thought to act somewhere besides the anabolic receptor, because they don't bind well in a test tube protocal, were recently found to be very active at the anabolic receptor in living creatures. So it's a situation where enough switches are flipped by these molecules for them to be potent anabolics in the real world, but not enough or the right kind of sub-switches are activated for them to be identified in an outmoded test-tube protocol.
So all anabolics function at the anabolic receptor, as far as we know in 2005. But they all "swipe the switches" a little differently. So they will have different "anabolic characters" you can identify, and that's what I use to plan cycles. And they do have different side effects, which can be factored in to plan around individual sensitivities.
Androgenization is really a side effect. Testosterone binds to the anabolic receptor (hitting more switches and co-factors than any other synthetic -- answering your question in the other thread) in muscle. It also binds to certain receptors in prostate, skin, etc, and these are called androgen receptors. While there is similarity in shape, don't forget that nature isn't that simple-minded, and prostate receptors don't look just like skin receptors, and neither looks just like the muscle receptors. The fact that testosterone hits them all doesn't mean other molecules must. What makes an anabolic "androgenic" is how many of these prostate, skin, etc receptors that the drug hits.
If you do a search for some guy's question about class I and class II drugs a week or two ago, you will see the article referred to and a different elaboration of these same points.
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