but then do the receptors down regulate or go back to normal once the nolva or clomid is stopped. I read a study where they used nolva for six months on pubertal gyno and it reduced the gyno in many of the cases, but after six months it became less effective the longer they used it and eventually did nothing, is this most likely related to the up-regulation?

I'm just not clear as to what down and up regulate really means and what affects it. I have the general idea, but what are the specifics if you don't mind.