HGH or human growth hormone is a protein hormone of 190 amino acids, which is synthesized and secreted by the Somatotroph cells (hence called Somatotropin) in the anterior pituitary. The genes for human growth hormone are localized in the q22-24 region of chromosome 17. The structure of HGH includes four helices necessary for functional interaction with the GH receptor. Structurally, HGH is homologous to prolactin and chorionic somatomammotropin and it appears as if the three share some evolutionary connection. The triad is known to promote growth and aid the lactogenic activity.
Human Growth Hormone Secretion
Synthesis and secretion of HGH are controlled by many factors such as exercise, nutrition, sleep, stress, and sometimes even by growth hormone itself. The control, however, is wielded by two hypothalamic hormones (Growth hormone-releasing hormone or GHRH and Somatostatin or SS) and one hormone present in the stomach (Ghrelin).
Functions of HGH
The human growth hormone contributes to the building up of the human body. HGH has two different types of effects on the human tissues and the human system as a whole – direct and indirect. The direct effects are the upshot of the growth hormone binding its receptor to the target cells. Indirect effects are stimulated by an insulin-like growth factor-I (IGF-I), a hormone secreted by the liver and other tissues in response to growth hormone action. In fact, most of the growth-promoting effects of HGH are the consequence of IGF-I acting on the target cells. Thus, it is apparent that HGH or Somatotropin plays a vital role in major physiological processes, including growth and metabolism.
HGH & Growth
The major role of growth hormone in effecting body growth is to stimulate the liver and various other tissues to secrete IGF-I. IGF-I. This, in turn, provokes the proliferation of Chondrocytes (cartilage cells), resulting in bone growth.
HGH & Metabolism
Human growth hormone has been found to have important effects on protein, lipid, and carbohydrate metabolism. These effects in some are direct, others indirect, and a few showing mixed effects.
Although height growth is an all-too-manifest effect of HGH on the human system, it has several other specific and essential functions. These functions range from protein synthesis to building muscle mass, calcium retention to mineralization of bones, stimulating the immune system to maintain fuel homeostasis, etc.
This is all about the real human growth hormone. Biosynthetic human growth hormone, also known as recombinant human growth hormone and abbreviated as rHGH was first used for remedial use in the U.S. in 1985. Since then, the biosynthetic variety of HGH has nearly sidelined the pituitary-prompted human growth hormone, especially in therapeutic use.