"Stew Meat recently posted an excellent post about nolva hindering gains. Like any antiestrogens, he said it will lower IGF-1, hence GH levels will drop. U would have gained more without nolva. Arimidex is the choice antiestrogen."
Arimidex will do the same thing. The reduction in GH/IGF levels is due to estrogen inhibition or reduction, so it doesn't matter the anti-estrogen.
"Methandriol dipropionate might help here since it does increases estrogen without aggravating gyno symptoms. MD also upregulate A/R, magnifying the gains u might make from the anabolics u r taking."
Methandriol, while on Arimidex, may be beneficial, since it is estrogenic, yet less so than estradiol. And since you have inhibited aromatase, it can't convert to methylestradiol.
Testosterone increases AR levels, this is not specific to MD.