Insulin should only be taken when your doctor prescribes it. There has been some concern about growth hormone injections increasing insulin resistance because some test subjects were found to develop symptoms initially when they were on a higher dose. However, with lower and more balanced dosing and as the therapy progressed the resistance to insulin decreased. More information about this can be found here: HGH and Diabetes
I know that some bodybuilders take HGH injections with insulin to try to improve the benefits they receive. I do not agree with this and believe they are risking their health.