GH and IGF-1 are negative regulators of GH release so an increase in either (from a GH injection) reduces the secretion of GH. IGF-1 is very difficult to obtain in a useable condition.... it must be handled very gently and have bee kept at a rather precise temperature at all times. One can stimulate IGF production through the use of an oral steroid during cycle. Dbol, for example, causes a rather extensive release of IGF during the first pass through the liver.
Is this true? I got this info from the main jin site so I can't post the link since it's a source.