How does the reverse-feedback system differ between test and GH?

If one's doctor thought it was a good idea (based on thorough labs, exam, etc...) to try GH, what is the risk of a permanent shut down?

I have heard - and don't know if it's correct - that using exogenous GH causes a rapid decrease in one's pituitary function (even to the point of causing pituitary atrophy?!?) Is this a horror story or is this real?

Let's say - among other things - you had really high triglycerides and visceral fat.

If you were to use GH for a period of say 6 months (1 iu, 5/2) as further theraputic trial, would one expect to see any significant difference in triglycerides or bodyfat?

If there were no benefit, if one stopped exo-GH, would you need to be worried about permanent shutdown? Could something like sermorelin help with this?