Which peptide produces the most growth hormone

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The Growth hormone is a peptide hormone that is 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 for the growth and differentiation of cells in childhood and adolescence. Its importance can also be seen in the fact that 40 percent of the cells of the pituitary gland are STH-producing cells. Read everything you need to know about growth hormone!

What are growth hormones?

Growth hormones are peptide hormones that are produced in the so-called somatotropic cells of the anterior pituitary gland. Their secretion is controlled by another region of the brain (hypothalamus), via two hormones:

  • The hypothalamic hormone somatoliberin (somatotropin-releasing factor) ensures that the pituitary gland increases
    Releases growth hormone.
  • The hypothalamus hormone somatostatin, on the other hand, throttles the secretion of growth hormone.

Various factors influence the release of somatoliberin and somatostatin and thus also the release of growth hormone.

STH release in a day-night rhythm

GH is released especially at night, in the deep sleep phases. During the day, the secretion of somatotropin fluctuates depending on various factors, namely indirectly via somatoliberin and somatostatin.

For example, low blood sugar (hypoglycemia), thyroid hormones, estrogens, dopamine, endorphins ("happiness hormones") and stress can promote the release of growth hormone.

Conversely, an excess of blood sugar (hyperglycaemia) and blood fat levels (hyperlipidaemia), progestins,
Adrenaline, being very overweight (obese) and cold slow down the release of STH from the pituitary gland.

What is the role of growth hormones?

The main effects of growth hormone include:

  • Promotion of the longitudinal growth of the bones after birth and in adolescents
  • Promotion of the growth of muscles and soft tissue (by boosting protein synthesis)
  • Promotion of fat loss to provide energy
  • Increase in blood sugar level and at the same time increase in insulin release (and thus a temporary decrease in blood sugar level)
  • Stimulates the formation of calcitriol (important for the mineralization of the bones)
  • Support of the immune defense (via the stimulation of T lymphocytes and macrophages)

Almost all of these effects of growth hormone are mediated by certain peptides, the production of which is stimulated by the hormone (especially in the liver): IGF1 and IGF2 (IGF = insulin-like growth factor).

What disorders can growth hormones affect?

If the pituitary gland is impaired, a deficiency in growth hormone can result. It can be congenital or acquired (for example through another disease, an injury or radiation). In children, a growth hormone deficiency results in reduced length growth. If the deficiency only occurs in adulthood, when the growth in length has already been completed, other symptoms may appear. For example, the fat reserves in the abdomen can grow, the blood lipid levels rise and the general well-being can be impaired.

An excess of growth hormone is also possible. It can be caused, for example, by a benign tumor of the pituitary gland (pituitary adenoma), which stimulates GH production. In children, too much somatotropin triggers gigantism (gigantism). In adults, on the other hand, too high a level of growth hormone leads to what is known as acromegaly: It is characterized, among other things, by the fact that protruding parts of the body (such as hands, feet, nose, ears, etc.) enlarge.

Laron's syndrome is a rare hereditary disease that is associated, among other things, with short stature. Those affected are due
a gene change (gene mutation) resistant to growth hormone.

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