The role of IGF-1
More evidence seems to suggest that there is plausible evidence for cycling between androgens and GH/IGF-1. At Least one study (10) demonstrates that IGF-1 plays a key role in regulating GnRH release via a Ras/Raf-1/Mapk induced pathway and an increase in the c-fos factor.
This makes a great case for starting IGF-1 after finishing androgens, both in aiding recovery, as well as keeping gains going. I'm not a big fan of IGF-1 due to the high cost and low returns, but no one can deny its use for athletes that need to maintain mass and keep gaining it while continuous steroid use is not an option.
(10)Zhen S, Zakaria M, Wolfe A, Radovick S.Regulation of gonadotropin-releasing hormone (GnRH) gene expression by insulin-like growth factor I in a cultured GnRH-expressing neuronal cell line.Mol Endocrinol. 1997 Jul;11(8):1145-55.