Our endocrine system and the mechanics associated with androgen regulation is more intelligent than what we give credit to. It isn't a simple intermittent starvation of AR receptors followed by a supraphysiological dose to help combat the endocrine's attempt at regulating androgen activity and striving for homeostasis.
From Pharmbiak:
Initially, yes, there is an up-regulation of the AR but after sustained elevated testosterone levels some desensitization occurs which leads to a decrease in mRNA levels acting as a negative feedback loop. In several cases it was found that the AR content increased but the binding affinity for androgens decreased resulting in a net loss of testosterone utilization. Essentially, after sucha long period of exposure the extra testosterone (above a certain point) became useless, whereas initially when first starting a cycle the extra free testosterone resulted in an almost linear dose-dependent effect curve. So, there's still benefit to an extended cycle (longer than 12 weeks) but the growth experienced isn't near what one expects an the beginning of a cycle... almost a sort of plateau effect. Leaving a 3 month gap or so between cycles resulted in a stronger initial response to the androgens.
http://www.bluelight.org/vb/threads/761131-Pct-on-test-only?p=13110674#post13110674