Your Pituitary gland is responsible for your hGH regulation, and as a child is imperative for your growth. Once you are an adult and fully grown hGH still has an important part to play. Not for growing, you have reached your height etc., but for regulation of many metabolic effects including pancreatic functions. People with damaged pituitary glands can easily develop diabetes (type II - type I is something you are born with and type II is acquired).
If you do not have a pituitary gland then drugs are prescribed to manage the metabolic deficits. Whether in your case hGH would be prescribed depends on many factors. Too many to go into here, and I am a paramedic lacking the in-depth endocrinology knowledge to know more than the basic things. What I can say is that there are more than "just" one type of hGH. For example, hGH messes with your IGF (Insulin Growth Factor) and and and.
As Bodybuilders, we often have the misunderstanding that hGH is just one compound, and to all intents and purposes for our needs - yes. But in reality, when we look at Unclem's issue, it is much deeper than just whacking in some hGH as that could lead to nasty, negative side-effects as the pituitary gland is no longer able to regulate other systems and could, from memory, cause shutdown of pancreas and spleen (I may be wrong, but that is what just came into my head from study years ago).
I will place some links below - feel free to have a read. I can go into some human biochemistry, but I fear that all I have is an undergrad qualification as part of my paramedicine degree which is over 20 years old (and my brain is SLOOOOOOW).
Human growth hormone (HGH) is a natural hormone your pituitary gland releases that promotes growth, helps maintain normal body structure and affects metabolism.
my.clevelandclinic.org
Human growth hormone (hGH) is a proteohormone secreted by the pituitary gland. It acts through binding to the hGH receptor, inducing either direct effects or initiating the production of insulin-like growth-factor I (IGF-I), the most important mediator of hGH...
link.springer.com
In spite of recent advance in understanding of the stoichiometry of 22-kDa human GH (22K-hGH) with cell surface hGH receptor (hGHR) and hGH-binding protein (hGH-BP) circulating in human plasma, that of 20-kDa hGH (20K-hGH) is poorly understood. To clarify this, mouse pro-B Ba/F3 cells stably...
pubmed.ncbi.nlm.nih.gov
This review summarizes the progress recently made through the approaches provided by DNA recombinant technology in the knowledge of the human growth hormone (hGH) gene and of the molecular basis of hGH deficiencies. The growth hormone gene is part of a family of five structural genes located on...
pubmed.ncbi.nlm.nih.gov