Among the innumerable diverse bodily functions of respiration and exchange of gases, digestion of food, circulation of blood, there exists a rather elementary but quite important operation of growth of cells, tissues. Just like every other task in the system, the development of organs is also regulated by a chemical messenger known as human growth hormone, abbreviated as HGH or hGH and also referred to as somatotropin, growth hormone, somatropin. Hormones are biochemical signalling substances synthesized in the body that are crucial for ensuring various operations, for example, insulin which promotes glucose absorption and regulates energy metabolism, testosterone for male reproductive functions and progesterone, estrogen for optimal fertility in women.
Growth Hormone And Its Structure:
The human growth hormone was discovered by the renowned Chinese-born American biochemist Choh Hao Li in the year 1955. Furthermore, he also determined the accurate biochemical configuration – the amino acid sequence of growth hormone in 1966 and worked along with his research team to successfully synthesize somatotropin in the lab for the first time in the year 1970. For his noteworthy fundamental discoveries and groundbreaking research accomplishments which opened up many new areas of biomedical science, Choh Hao Li was awarded the prestigious Albert Lasker Award For Basic Medical Research in 1962.
The human growth hormone is secreted by the pituitary gland located at the base of the head, by specialised organelles called neurosecretory nuclei present in the hypothalamus segment of the brain. It is a peptide hormone consisting of 191 amino acids arranged in four helical forms and has a molecular weight of 22, 124 Daltons, dalton being the unified atomic mass unit used for measuring molecular weight of substances.
Functions Of Human Growth Hormone:
The human growth hormone or somatotropin performs several vital functions in the system, including:
- Boosts proliferation of cells and regeneration of tissues in the body, since it is a mitogen – a protein that triggers cell division to take place
- Promotes healthy growth in height and fosters optimal weight gain in children and adolescents
- Augments bone density and muscle mass
- Ensures the balance of body fluids and maintains normal body composition of fats, water and blood
- Controls glucose synthesis, uptake by cells and protein, lipid metabolism
- Bolsters energy levels and improves productivity, overall quality of life
- Enhances brain health, cognitive functions and heart wellness
Adverse Effects Of Imbalance In Growth Hormone Levels:
While the pituitary gland regulates the secretion of human growth hormone in normal, healthy individuals, in some instances its activity is hindered which leads to hormonal imbalance of somatotropin and prompts certain related health issues.
When growth hormone levels are lower than normal, depending upon the age of the individual affected, distinct health complications arise. In children, it affects functions of liver proteins, while also resulting in short stature due to lack of growth, delay in attaining puberty and hampered sexual development. Growth hormone deficiency in adults induces destruction of bone cells leading to debilitating ailments of fractures and osteoporosis with fragile bones and a decline in productivity. In rare circumstances, low levels of somatotropin in adults can cause a type of non-cancerous tumour known as pituitary adenoma.
The excessive synthesis of growth hormones causes a slow-growing pituitary adenoma which instigates headaches, poor vision, massive pressure on the optic nerve as it becomes larger in size. An extremely high level of somatotropin results in acromegaly, wherein the jaws, fingers and toes in the body are bigger and thicker compared to normal. Although they occur in seldom instances, when surplus HGH levels are exhibited in childhood, it leads to pituitary gigantism, in which the affected individual portrays an abnormally large height and weight at a very young age.