Human growth hormone (abrev. hGH) is a
protein that is produced in the [pituitary gland]
? that stimulates the
liver to produce somatomedin
?s, which, in turn, stimulate the growth of bone and muscle. It is the most abundant
hormone produced by the pituitary gland in the brain. The production of hGH peaks during the rapid-growth phase of adolescence
?, then steadily drops with increasing age. HGH in the blood is only active for a few minutes. In this short time, it activates the production of the
Insulin-like growth factor 1 (IGF-1) in the liver. hGH also stimulates the
immune system, and increases body mass.