Functions of Growth Hormone in Human Body



Somatropin or somatotropic hormone is the hormone that strengthens the bones, affects the linear growth in children and adolescence, and participates in many life processes of the body. It is synthesized in the anterior part of the pituitary gland, the central endocrine gland, through which the hypothalamus, one of the brain parts, directs the activity of the endocrine system.

Characteristics of the hormone

In addition to linear growth, somatropin exerts an anabolic effect on the body, and thereby new cells are constantly formed and renewed in the human body, the protein synthesis is accelerated, and its degradation is inhibited. Another feature of the hormone is that it reduces the fatty layer, contributing to fat burning and providing a greater ratio of muscle mass to fat. Growth hormone regulates carbohydrate metabolism, increases the absorption of calcium by bone tissue, impacts the pancreas function.

The somatotropic hormone also affects the central nervous system: somatropin is produced not only by the pituitary gland, but also by the hippocampus. This is the olfactory center of the brain, which is involved in forming human emotions and short-term memory to long-term memory transiting (fixing memories). Its production in the hippocampus increases with a high concentration of estrogens in women (in the pituitary gland, on the contrary, it decreases), in both male and female sexes – under severe stress.

In the early 90’s of the last century, scientists came to the conclusion that injection of a somatropin analogue may promote anti-aging effect. Advertising has taught this news as an axiom, which many people still consider be true. In fact, further experiments in mice demonstrated the opposite results: a low level of somatropin, a low sensitivity of cells to it, as well as a reduced hormone synthesis in the embryo significantly increases life expectancy.

Regulation of somatropin synthesis

Receptors interacting with the growth hormone are found throughout the human body, including in many areas of the brain and spinal cord. In general, the growth hormones affect the body through a protein called insulin-like growth factor (IGF). It is the mediator between somatropin and the body cells and is formed in the liver.

Synthesis of the hormone is regulated by somatostatin and somatoliberin, which are produced by hypothalamus (one of the brain parts). The first reduces production of somatropin, the other increases. The somatropin production is also enhanced by:

  • hunger hormone ghrelin (synthesized in the stomach)
  • proper night’s rest
  • physical activity and exercises, which contribute to the growth of muscles
  • increase of androgens during puberty both in female and male
  • low glucose level
  • use of such amino acids as arginine, ornithine, lysine, glutamine

The synthesis of somatropin is reduced at a high concentration of the mediating protein of the IGF that is formed in the liver. Its production is decreased with an excess of blood glucose and an increased amount of free fatty acids. Its level is reduced by the adrenal hormones glucocorticoids, female sex hormones estrogens.

Alcohol bocks the somatropin synthesis, so alcohol abuse of the mother during pregnancy or of the father before conception may result in the child’s short stature. At an older age, alcohol does not allow cells to grow, develop or renew.

Interaction with hormones

Production of somatropin is strongly dependent on insulin, which is formed in the pancreatic gland. This is due to the fact that the growth hormone contributes to growth of muscles and tissues, while burning fat, what immediately affects carbohydrate metabolism: the body increases production of glucose to provide the body with the necessary energy and to deliver nutrients to each cell. To prevent excess sugar in the body, the pancreatic gland starts to produce insulin and leads it back to normal.

It is safe to say, that the growth hormone increases glucose concentration in the blood. For example, the use of somatropin in bodybuilding for the purpose of increasing the muscles and giving them a beautiful form is dangerous: if not properly used, the pancreatic gland does not cope with this load and ceases to produce insulin in the right amount, which leads to diabetes.

If the body lacks insulin, the growth hormone reduces its effect on the body and stops stimulating the formation and renewal of new cells and tissues. The lack of insulin in children also explains the low linear growth and developmental delay.

Sex steroid hormones affect the proper functioning of somatropin: male androgens (increasing its production) and female estrogens, which reduce its synthesis. Secretion of growth hormone depends largely on the thyroid gland producing iodine-containing hormones that take an active part in metabolism, as well as calcitonin, which controls amount of calcium in the blood and stops destruction of bone tissue.

That is why thyroid disease in children and insufficient production of sex hormone also causes short stature, physical and even mental developmental problems.

Concentration of hormone

During the day, the peak of somatropin in the blood is fixed every three to four hours. The greatest amount of hormone is fixed at night, an hour or two after the person falls asleep. Therefore, people with insomnia suffer from a hormone deficiency.

The highest concentration of somatropin is recorded in children during the intrauterine development, during the fourth to sixth month of pregnancy (in this period, somatropin is 100 times higher than the adult’s). The hormone level in children after birth reaches the maximum values several times: at a teenage and young age (these are the periods of intensive growth and puberty).

After twenty, its development begins to decline, and it is produced in very small amounts in old age. It happens even earlier if a person abuses alcohol.

The increased amount of somatropin in children leads to gigantism. Acromegania develops in adults (usually it is consequence of gigantism in children or reaction to incorrect use of an artificial hormone, when it is administered in a dosage typical for a growing body in children). It results in thickening of bones, coarsening of facial features. In this case, such complications as compression of nerves, reduction of muscle strength, and increase in insulin resistance of tissues are possible. There may be an adenoma – a benign tumor.

Lack of somatropin in children is usually related to genetic pathologies and is the cause of short stature and delayed sexual development. It can affect mental activity, but only in combination with other hormonal problems, for example, thyroid gland problems or due to underdevelopment of the pituitary gland. Lack of somatropin in adults causes accelerated obesity. Somatropin deficiency may also be the cause of poor memory and undeveloped cognitive functions (occurs in case of pituitary gland issues).

Problems with somatropin may be associated with Laron syndrome. This disease is characterized by a high concentration of growth hormone with a reduced content of IGF, which delivers it to the body tissues. For this reason, injections of somatropin have no result. This disease is inheritable and causes dwarfism.

The problem develops differently in children: a baby may be born already small, and may have a normal body length. The growth is delayed with age, the disease is accompanied by minor adiposity, the «doll face» is formed, high voice, delay in sexual development. The disease does not affect intellectual abilities.

Therapy of somatropin normalisation

If the body of a child lacks somatropin, a course of therapy is prescribed, which involves administration of hormone analog. For example, it could be a drug known as Jintropin: it is a complete analog of human hormone and is considered one of the purest drugs. It is very important to finish the therapy before the end of puberty. Nowadays, it is the best method to solve the problem of dwarfism.

Studies have shown that somatropin administration improves mood not only in people with growth hormone deficiency, but also in patients suffering from depression. However, it is necessary to act reasonably here, since excess of hormone promotes development of depression and problems with the central nervous system.

In addition, if the therapy lasts long time, an elevated concentration of hormone may lead to hypertension, hyperglycemia and other problems. For this reason, it cannot be used for a long time that is why scientists are trying to develop a drug that has an effect on the CNS similar to somatropin, but does not affect other receptors.

Indications for use of Jintropin are also fractures, long non-healing wounds, ulcers in the digestive system, violation of lipid metabolism. In the form of a complex therapy course it is used to treat osteoporosis (a disease where decreased density of bone tissue and its broken structure are observed). It is prescribed for children with chronic renal failure, if the kidney function is reduced by more than fifty percent.

Usage in sports

The main reason for using somatropin among athletes is its ability to reduce amount of subcutaneous fat, to increase the dry mass of muscles, connective tissues and to increase the volume of muscle cells due to fluid accumulation. It also reduces the likelihood of injury, which is associated with its ability to strengthen bone and connective tissue (tendon, cartilage). In this case, somatropin accelerates restoration of damaged tissues of the body after injuries.

The growth hormone does not affect the muscle strength. One of the reasons for this is that muscle growth occurs due to fluid retention in the body as a result of injections. That is why, the course of hormone will be absolutely ineffective in power sports. In addition, artificial growth hormone does not affect the increase in endurance or productivity; on the contrary, a person becomes tired more quickly and restores strength longer.

This leads to many side effects, including development of diabetes, hypertension and other diseases. That is why, the artificial somatropin was banned in sport in order to preserve the health of athletes.

Despite the ban, many athletes continue to use this hormone in the form of a course. Mostly it concerns bodybuilders who can use a solo drug (meaning usage of only one hormone) or use in combination with other hormones, for example, insulin and thyroxine (one of the thyroid hormones).

One of the most popular synthetic analogues of somatropin is Jintropin, which is used both solo and in combination with insulin. The drug promotes growth and multiplication of cells, and this applies not only to muscles and bone tissue, but also to connective tissue, adrenal glands, thyroid gland, liver. The usage of Jintropin allows to heal wounds very quickly and to restore bones after fractures.


If you decide to take Jintropin or another growth hormone, you should not forget that this is a drug that may have a very negative effect on the human body, when the course is selected incorrectly. Therefore, you need to study the instructions carefully, read the contraindications and pass the appropriate tests to choose the correct dose of Jintropin. The course of this drug is categorically contraindicated to persons who have:

  • hypersensitivity (allergy) to components of Jintropin
  • any malignant tumors (hormone stimulates their growth)
  • in conditions that pose a danger to human life (after heart and abdominal surgeries; presence of acute respiratory failure)
  • pregnancy and lactation

Use the drug carefully with diabetes mellitus, increased intracranial pressure, hypothyroidism, when the thyroid gland produces hormones in insufficient quantities. Taking growth hormone, it must be borne in mind that Jintropin and alcohol are incompatible. Growth hormone has already the strongest effect and in combination with alcohol, it is difficult to predict the body’s reaction. This may be both the side effects indicated in the instructions and completely unpredictable consequences associated with the effects of alcohol.

During usage of hormone, the body undergoes additional stress and in combination with alcohol, this effect will increase. As a result, the body will be exhausted, and muscle growth will be zero. The same applies to drinking alcohol during therapy.

Delivery of medical tests

Before deciding to take the course of Jintropin, it is necessary to pass medical tests, so the doctor could correctly prescribe the scheme of taking the drug. It is necessary to determine the glucose level to check presence of diabetes (its symptoms are expressed poorly in the initial stages). You also need to check for cholesterol. If the analysis has shown its increased amount, it is advisable to abandon the use of Jintropin, since it may enhance the synthesis of all steroid hormones leading to severe consequences.

Urine analysis is also the mandatory analysis. Decoding the data may show presence of inflammatory processes leading to various failures. In this case, the use of Jintropin and any other growth hormone may stimulate this process. It is also required to pass tests to check for a malignant tumor, the existence of which many people do not suspect until the third stage. If there is any, the course of Jintropin and any other growth hormone should be abandoned, since it stimulates growth of metastases.

It is desirable to pass tests once a month during the course (the course lasts usually from two to six months). It is necessary to know the body’s reaction to the injected hormone, and to take action in time when a problem is detected. It is understood, that the drug and the course should be prescribed by a doctor. “

If swelling, vomiting, nausea, increased intracranial pressure, fingers began to grow numb, breasts began to enlarge you need to consult a doctor and you may have to cancel Jintropin. These are signs of side effects, which indicate the emergence of malfunctions in the body due to usage of hormone.

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