Growth hormone

The growth hormone is a peptide hormone that is formed 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 from the fact that 40 percent of the en venta Tamoxifen Citrate en Espana pituitary cells are STH-producing cells. Read everything you need to know about growth hormone!

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What are growth hormones?

Growth hormones are peptide hormones that are formed in the so-called somatotropic cells of the anterior pituitary lobe. Your 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 releases more
  growth hormone.
• The hypothalamic hormone somatostatin, on the other hand, reduces growth hormone release.

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

STH distribution in a day-night rhythm

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

For example, hypoglycaemia, thyroid hormones, estrogens, dopamine , endorphins («happiness hormones») and stress can promote the release of growth hormone.

Conversely, an excess of blood sugar (hyperglycaemia) and lipid levels (hyperlipidaemia), progestogens,

adrenaline, severe overweight (obesity) and cold can slow down the release of STH from the pituitary gland.

What is the function of growth hormones?

The main effects of growth hormone include:

• Promoting bone length growth after birth and in adolescents
• Promote muscle and soft tissue growth (by boosting protein synthesis)
• Promotion of fat loss for energy supply
• Increase in blood sugar levels and at the same time increase insulin release (and thereby a temporary decrease in blood sugar levels)
• Stimulation of calcitriol formation (important for bone mineralization)
• Immune defense support (via stimulation of T-lymphocytes and macrophages)

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

Which disorders can affect growth hormones?

If the pituitary is malfunctioning, growth hormone deficiency may result. It can be congenital or acquired (due to another illness, injury, or radiation). A growth hormone deficiency in children results in reduced growth in length. If the deficiency occurs only in adulthood, where the growth in length has already been completed, other symptoms may appear. For example, the fat reserves on the abdomen can grow, the blood lipid levels rise and the general condition can be impaired.

An excess of growth hormone is also possible. It can be caused, for example, by a benign pituitary tumor ( pituitary adenoma ) that boosts STH production. Too much somatotropin triggers gigantic growth in children. In adults, however, a too high level of growth hormone leads to so-called 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 syndrome is a rare inherited disorder that is associated with short stature, among other things. Those affected are

resistant to the growth hormone due to a gene change (gene mutation).