|Ribbon model of somatropin based on crystal structure.|
Existing structural: , , , , , , , ,
|Properties of human protein|
|Mass / length primary structure||191 amino acids|
|Secondary to quaternary structure||1-, 2-, 3-, 4-, or 5-mer in homo- and heteropolymer combinations|
|Gene names||; GH-N, GHN, GH, hGH-N|
|ATC code||H01 AC01|
Somatropin or somatotropin (also called somatotropic hormone ) is a proteohormone that occurs as a growth hormone in the human and animal organism and is formed in the brain in the anterior lobe of the pituitary gland .
There are a number of synonyms and abbreviations for the somatropin:
- Somatotropic hormone (STH)
- Human Growth Hormone (HGH)
- Growth Hormone (GH)
- Growth hormone (WH)
- Somatropin ( INN )
The primary structure of human somatropin consists of 191 amino acids with a molecular mass of 22,125 Da . There are species-specific variants of the hormone. The tertiary structure consists of four α-helices with two intramolecular disulfide bonds .
Education and Regulation
Somatropin is produced in the α cells of the anterior pituitary gland . Its spurt-wise release is regulated by the hypothalamus with its somatropin-releasing factor (SRF, GHRH growth hormone-releasing hormone, GRF, somatoliberin) and somatostatin . Most somatropin is produced during sleep . The Puberty is the age with the ausgeprägtesten somatropin production.
A lack of an energy substrate ( hypoglycemia , fasting , physical activity), an increase in the serum level of certain amino acids (e.g. through a high-protein diet), fever and psychological stress are secretion stimuli for somatropin. Somatropin is negatively regulated by somatostatin , an inhibiting hormone ( Growth-Hormone-Inhibiting-Hormone, GHIH), which is produced in the pancreas and hypothalamus .
Specifying a normal value for the concentration of somatropin would be wrong, since there is a daily rhythm and a life rhythm of secretion . There are also factors that stimulate acute secretion. That is why several values are usually taken in a daily profile.
The somatropin suppression test has proven itself in the diagnosis of acromegaly and giant stature . Autonomous somatropin secretion is used when the somatropin level does not fall below 1.0 µg / l during oral glucose exposure (oGTT, 100 g glucose).
The individual determination of somatropin is unsuitable for the diagnosis of a somatropin deficiency because of the episodic (pulsatile) spontaneous secretion and the resulting phases with undetectable hormone levels. The determination under stimulation is possible with the following methods:
- Limit values: 11.5 ng / ml for people of normal weight with a BMI ≤ 25 kg / m², 8 ng / ml for overweight people with a BMI between 25 and 30 kg / m² and 4.2 ng / ml for obese people with a BMI> 30 kg / m²
- Insulin Hypoglycemia Test (STF)
- Limit values: severe deficiency at <3 ng / ml; partial deficiency at 3–7 ng / ml; normal at> 16 ng / ml
Effect, deficiency and overproduction
Somatropin is essential for normal growth. With a decreased production or a decreased response of the cells to somatropin, it comes to a short stature . Overproduction results in gigantic growth or acromegaly (excessive growth in the not yet ossified areas in the acres such as the nose, chin, fingers and cranial bones as well as in all soft tissues (e.g. cardiomegaly )).
In adulthood, a lack of somatropin leads to a variety of symptoms:
Also, a lack of somatropin leads to too
- an increased cardiovascular risk profile,
- decreased quality of life and
- the increased use of medical services.
These symptoms are associated with a reduced life expectancy.
Somatropin works indirectly by attaching to the somatropin receptor , which is a transcription factor and increases the expression of the protein insulin-like growth factor-1 (IGF-1). This in turn binds to its receptor ( IGF1R ), which is also a transcription factor and controls the production of a large number of other proteins. If the somatropin receptor is changed by mutations , the cells do not respond or respond less to somatropin, which is referred to as somatropin resistance or Laron's syndrome .
More precisely, somatropin mainly affects the following organs:
Anabolically, it acts primarily on muscles , liver and bones, in that it leads to increased absorption and utilization of amino acids. Somatropin increases the blood sugar level (through glycogenolysis ) and has a lipolytic effect on the fat cells, i.e. it breaks down fat.
Use as a medicinal substance
Somatropin has been used to treat short stature since 1963 when it is caused by a lack of growth hormone. It was obtained from the pituitary glands of the dead until it was banned worldwide in early 1985 because it resulted in the transmission of AIDS and Creutzfeldt-Jakob disease in patients and subsequent deaths. Somatropin has been produced recombinantly since December 1985. Today, growth hormone is also used for the therapy of low body height if another underlying disease causes this short stature, for example in Ullrich-Turner syndrome , Prader-Willi syndrome , in chronic kidney failure or in short stature as a result of intrauterine growth retardation ( SGA, Small for Gestational Age). It has also been used for a number of years as a replacement therapy for severe growth hormone deficiency in adulthood.
Synthetic somatropin is used as an "anti-aging" agent and there is no evidence of long-term benefit. It is often misused due to its muscle-building properties in bodybuilding and other sports. For this purpose it is sometimes combined with testosterone , insulin , trenbolone and the thyroid hormone triiodothyronine (T3). In the meantime, however, dangerous total counterfeit drugs allegedly containing somatropin have emerged, which were intended for use in the bodybuilder scene. In the doping scene, somatropin is generally regarded as an expensive "miracle weapon".
Initial results from the Thymus Regeneration, Immunorestoration, and Insulin Mitigation study raised ethical questions such as "Do we want a world where millions starve and others grow old?"
Somatropin has been reliably detectable since 1999 using a method developed by the German hormone researcher Christian Strasburger . Another method was developed by Peter Sönksen in 2000.
Genotropin (D, A, CH), Humatrope (D, A, CH), Jintropin (RU, CN ), Norditropin (D, A, CH), NutropinAq (D, A), Omnitrope (D, A, CH), Saizen (D, A, CH), Zomacton (D, A)
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- PDB 1hgu
- Somatropin data sheet (PDF) at EDQM , accessed on June 6, 2011.
- UniProt P01241
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- European Medicines Agency confirms positive benefit-risk balance of somatropin-containing medicines. EMA press release, December 15, 2011.
- Customs investigation warns of totally counterfeit medicine "SOMATROPE". ( Memento from January 1, 2011 in the Internet Archive )
- Plagiarism pills make biceps dwindle. In: Der Spiegel. 42/2009.
- "Can We Restore Thymus Function to Cheat Death?"
- "He who lives forever makes no room for others" Zeit Online from July 15, 2019
- Evidence of doping with HGH ( memento of February 18, 2009 in the Internet Archive ).
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