I am pretty sure that Natty GH suppression using regular, stable level, prolonged use has been covered and is indeed fact.
This is the main reason protocols differ between 4iu x7 days a week and 10iu x3 days/wk/.
The dosage is the same, but the latter examplke gives a more pulsatile injection pattern.
The largest natural GH pulses are when someone falls into REM sleep usually, so dosing in the morning/early afternoon is recommended so as to avoid large levels still being in the system when you gop to sleep - thus hopefully avoiding negative feedback.
IIRC - i believe the negative feedback loop is triggered by the exogenous GH levels affecting the levels of GHRH, and thus the secretion of natural GH - as i said, if i remember correctly that is.
There are alot of articles online that give you the answers and it is obviuosly just laziness that brings you to post. Which is the exact reason why i am not checking the information above to confirm and elaborate - being a drug i can't afford to use and thus have not read up on in detail.