Growth hormone is a peptide hormone produced in the pituitary gland in the brain. It is also called “growth hormone” (GH), “human growth hormone” (HGH), somatotropic hormone or somatotropin (STH). The hormone is particularly important in childhood and adolescence for the growth and differentiation of cells. Its importance can also be seen in the fact that 40 percent of the cells in the pituitary gland are STH-producing cells.
What are growth hormones?
Growth hormones are peptide hormones that are produced in the somatotropic cells of the anterior pituitary gland. Their secretion is controlled by another brain region (the hypothalamus) via two hormones:
- The hypothalamic hormone somatoliberin (somatotropin-releasing factor) ensures that the pituitary gland increases releases growth hormone.
- The hypothalamic hormone somatostatin, on the other hand, reduces growth hormone secretion.
Various factors influence the release of somatoliberin and somatostatin and thus also the release of growth hormone.
What is the function of growth hormones?
The most important effects of growth hormone include:
- Promotion of bone growth after birth and in adolescents
- Promote muscle and soft tissue growth (by boosting protein synthesis)
- Promotion of fat breakdown for energy supply
- Increase in blood sugar levels and at the same time increase in insulin secretion (and thus a temporary decrease in blood sugar levels)
- Stimulating calcitriol formation (important for bone mineralization)
- Support of the immune system (by stimulating T-lymphocytes and macrophages)
What disorders can growth hormones affect?
When the pituitary gland is impaired, growth hormone deficiency can result. It can be congenital or acquired (such as from another disease, injury, or radiation). In children, growth hormone deficiency results in reduced growth in length. If the deficiency only occurs in adulthood, when growth in length has already ended, other symptoms can appear. For example, the fat reserves on the stomach can increase, blood lipid levels rise and general well-being can be impaired.
An excess of growth hormone is also possible. For example, it can be caused by a benign tumor in the pituitary gland (pituitary adenoma) that boosts STH production. In children, too much somatotropin triggers giant growth (gigantism). In adults, on the other hand, too high a level of growth hormone leads to so-called acromegaly: It is characterized, among other things, by protruding body parts (such as hands, feet, nose, ears, etc.) enlarging.
Laron syndrome is a rare hereditary disease that is associated with short stature, among other things. Those affected are due to a gene change (gene mutation) resistant to growth hormone.
Kleine, B., & Rossmanith, W. G. (2016). Hormones and the endocrine system. Cham: Springer International Publishing.
Schmidt, R. F., & Thews, G. (Eds.). (2013). Human Physiology. Springer Science & Business Media.