so what your saying is testosterone itself doesn have any psycho active properties...but it does set off a sort of chain reaction that causes the psych change ?
No, what I'm saying is that the body has multiple opoid receptors: mu, kappa, delta as an example, and there are subtypes of each of these receptors These receptors are located directly on the nerves which are affected, so the drugs effects are direct without the insitution of any additional mechanisms.
Where as testosterone is essentially taken up by a single recptor type-- Free T is transported into the cytoplasm of a cell, where its taken up by the Androgen receptor or its converted to DHT, which binds to the androgen receptor. This single androgen receptor is really what causes the effects you see from Testosterone. Once that receptor is activated, it sets off a cascade of events that leads to the effects that are seen--for example increasing DNA transcription, leading to mRNA synthesis leading to ribosomal synthesis of cellular proteins leading to increased muscular cell size. There are steps in the pathway, its not "direct".
As far as psychological effects of testosterone, NO, I am NOT saying that Test has no psychological effects. The thing is the effects of test come from activation of other mechanisms. I am not aware of there being direct androgen receptors on nerve cells like there are opoid receptors on nerve cells, however, there is differences in the size of the male and female brain that are associated with androgen administration (neutered male dogs will have a proportionally smaller brain than intact male dogs of the same age, breed, and physical size). That makes me think there has to be a direct effect on nervous tissue in some way.
I know from my own experience, I have seen a definite difference in moods since starting HRT. I can focus again and think directly at what is going on. I have always been a posterchild for ADD, but now thoughts aren't bouncing all over the place without direction and I don't have the same mental fog I did 2 months ago. Now, that said, i'm still not at a normal Test level with HRT. I don't know how things will be once I get back to "normal".