They do use it for Parkinson's, and certain forms of male perf. enhancement, but it's also a good pituitary poison. That means that it turns off secretion of LH, FSH, Prolactin, etc. Combine that with some nolva and you have a good no lacto combo. There is a lot of good info distributed over a variety of theads on this board if you try a seaarch here. And even though they would be bad to use during PCT, dopaminergics do promote GH release to varying degrees.
Apologies, but I have to seriously disagree with the vast majority of what you're saying:
alter dopaminergic tone in the brain (particularly via D2)
or prolactin, and they produce a similar signaling cascade to the hypothalamus which inhibits the release of GnRH (gonadotrophin releasing hormone). So for starters, dopamine doesn't directly affect the pituary in terms of endocrine activity, hence the idea of DA-agonists as "pituary poison" is ludicrous (laughable at best). It's the hypothalamus that interacts with the pituary in response to alterations in dopamine signaling &/or prolactin on an indirect level.
Okay, so DA+ --) picked up by the hypothalamus --) inhibits GnRH release in the pituary.
From there, as we know, GnRH causes pituary stimulation that resuls in the release of LH and FSH. LH binds to Leydig cells in the testes, where tesosterone and estrodiol are synthesized as a response.
So I can see where he's going astray: it looks like "take dopaminergic --) inhibit GnRH release --) inhibit LH release --) lower testosterone."
Problem is that it's more complicated than that, because despite the fact that DA stimulation causes a relay that prompts a direct reduction in GnRH release, this SAME STIMULATION also kills prolactin levels, and there is invariably an inverse relationship between prolactin and testosterone. So it ends up looking a little something like this:
DA + = less prolactin --) overturns its own inhibitory effects on GnRH --) a net gain in 'downstream' testosterone synthesis. This is the accepted human model (1).
As long as your are dosing your dopaminergic in the morning to coincide with your body's natural basal dopamine and prolacin rhythms, the drug (bromocripine or even pergolide) will act in a stimulatory fashion. It is a mistake however, to dose outside of this rhythm, either via multiple daily dosings or by using longer-acting dopaminergics.
This is just from a hormonal/endocrine standpoint: it is also prudent from a neural and psychological angle.
1. Nakagawa K et. al. Relationship of changes in serum concentrations of prolactin and testosterone during dopaminergic modulation in males. Clin Endocrinol (Oxf) 1982 17:345-52.
