Cell proliferation with hgh or igf? And muscle cell proliferation? There's no such science for humans or is there for igf/growth hormone deficient humans? as far as exogenous hgh.
There isn't going to be a study geared for our purposes that just states what we want to know. What we do is gather several results of studies combined with theories that have some backing either it be real world experience or makes sense on paper and come to our own conclusions. People need to stop looking for these unicorn studies that are never going to happen.
Here's what I understand, it's not cut and dry, further research still needs to be done. Credit goes to b_cornelius for a lot of the later information I learned, maybe he can chime in if we keep this conversation civil and keep the BS bro-science out.
Exogenous HGH/IGF is going to attach to extracellular receptors, it can't crack the barrier and get into the cell at a intracellular level. This doesn't mean they don't work, they just work from the "outside" as opposed to the "inside". This is mainly how igf produced in the liver works (versus igf/mgf produced within the muscle cell).
More effective would be at the intracellular level, which happens to be triggered by training. This is why someone can't just take PEDs and grow. I mean sure you can take HGH and diet and take advantage of the fat loss and anti-aging effects but you aren't going to start packing on any muscle. But take two people who train, let's assume this is controlled for shits and giggles, one on HGH/IGF and one not on anything (natural let's say) and you will find the PED user is going to grow muscle at a quicker rate.
Now during and after training your body will start producing several hormones for recovery, HGH/IGF/MGF, etc. Some of this is intracellular such as the MGF/IGF produced within the cell that attaches to nuclear receptors, this is the most effective. From what I understand one of the (only) ways to increase the production of intracellular MGF is by taking GH/slin when training.
I know this doesn't answer your question directly brother, but I think you can grasp the picture I am attempting to paint.