Growth hormone – somatotropin. What does excess and deficiency of GH mean?
Growth hormone, or somatotropin, plays a major role in child development. It affects growth, body weight, but also many other processes that take place in the body. What is the normal concentration of growth hormone? What are the effects of its excess, and what are the effects of GH deficiency? Let’s check what is worth knowing.
Growth hormone – what is somatotropin
Growth hormone, or somatotropin (GH), belongs to the group of protein hormones, or polypeptide hormones. The function of somatotropin is to stimulate the growth of organs and long bones in the body. But that’s not all, it is also involved in stimulating nucleic acids and increasing protein synthesis and cell division – in short, all the processes that are associated with growth and development. The pituitary gland (anterior lobe) is responsible for the production of GH, while its dysfunction can result from the development of a gland tumor. The secretion of growth hormone is pulsatile and is related to gender, age and time of day. GH in humans is made up of 191 amino acid residues, the amount of somatotropin entering the body is regulated by somatostatin, which inhibits its production, and somatoliberin, which increases its secretion. Growth hormone is secreted most intensively at night, during sleep. Growth hormone disorders are primarily associated with damage to and dysfunction of the pituitary gland – so they can result in too little or too much height. Growth hormone testing is performed, among other things, in the diagnosis of the causes of short stature or gigantism in children or too tall, the so-called acromegaly in adults, in cases of suspected tumors of the pituitary gland producing hormones – including somatotropin, as well as in the course of treatment of patients with recombinant growth hormone.
Growth hormone – effects and impact on the body
How does growth hormone affect the body? It affects it by stimulating and producing peptides mediated by the liver and other tissues, namely: somatomedin IGF-1 and IGF-2. The effects of growth hormone are: stimulating the growth of long bones and organs, as well as weight gain, GH plays a key role in the synthesis of nucleic acids, participates in the process of protein synthesis and cell division, affects carbohydrate metabolism, improves skin condition, and takes care of mood and concentration. The use of growth hormone over a long period of time leads to an increase in insulin secretion in the pancreas, but also affects adipose tissue by increasing lipolysis thereby limiting lipogenesis, and this will lead to an increase in the concentration of free fatty acids in blood plasma.
Growth hormone (GH) testing
Testing growth hormone levels is a test that involves drawing blood from the elbow vein several times – to collect serum. The patient should come to the test on an empty stomach, so the last meal can be eaten no later than 8 hours before. The growth hormone stimulation test is performed on an empty stomach and after the administration of insulin, arginine and dopamine. The GH inhibition test involves the administration of glucose orally. The substances administered to the patient are analyzed to check their effect on GH levels. Such a test is performed when diagnosing short stature, evaluating whether to check whether treatment based on taking growth hormone is effective, or when a GH-stimulating tumor is suspected. Growth hormone deficiency can be related to congenital, acquired or unknown causes, while excess growth hormone is most often due to the presence of a tumor that enhances the production of this gland.
Growth hormone standards
When GH levels are tested, growth hormone norms in adults are between 1 and 12 µg/l. Growth hormone norms in children and newborns are at 10 – 30 µg/l. GH level tests are carried out on doctor’s orders, the result depends on the patient’s age and gender. The amount of growth hormone is related to, among other things: heavy exercise, sleep, overstarvation and estrogen levels. The stimulation test is more applicable when diagnosing GH excess or deficiency in adults and children, while inhibition tests will be more helpful when confirming or ruling out a tumor that is stimulated by growth hormone production.
Excess growth hormone in children
Excess growth hormone in children results in gigantism, which is associated with excessive growth of long bones, such as the femur, tibia, or humerus, and tissues. If left untreated, pituitary gigantism results in a child who can grow as tall as 210 centimeters in a short period of time. What’s more – high blood pressure or delayed sexual maturation can also be symptoms of accompanying gigantism.
Growth hormone deficiency in children
Somatotropin deficiency in children, is characterized by growth that is too low for their age and delays in physical development. In addition, too-low levels of growth hormone can also be accompanied by hypoglycemia, prolonged jaundice, fat accumulation in the abdominal area, too-small hands and too-short nose.
Symptoms and effects of excess growth hormone levels in adults
Excess growth hormone in adults can lead to acromegaly – growth of soft tissues, such as feet, hands, jaw, nose, earlobes and enlargement of the heart and tongue. In adults, too high levels of the hormone can result in deformities, hypertrophy and joint and bone pain, as well as enlargement of internal organs, increased sweating, excessive hairiness, thickened skin, diabetes and insulin resistance.
Symptoms and effects of growth hormone deficiency in adults
In adults, growth hormone deficiency can appear through symptoms such as: decreased energy and vitality, abnormal emotional reactions, feelings of anxiety, depressive states, isolation, increased abdominal obesity, decreased ability to exercise, malaise, paleness and sweating of the skin coverings, increased wrinkles, decreased thickness and dryness of the skin, thinning of hair on the head and body, decreased activity of sweat glands, hypertension with progressive circulatory insufficiency, disorders of lipid metabolism, that is, an increase in cholesterol and a decrease in good cholesterol and an increase in triglycerides. Somatotropin affects the structure, proportion and composition of tissues in the body. Adults with GH deficiency show increased fat mass, mainly visceral fat, and decreased lean body mass.
Growth hormone treatment – effects and side effects
What is growth hormone treatment like in Poland? The administration of recombinant human growth hormone (rhGH) is reimbursed for children diagnosed with idiopathic pituitary insufficiency, chronic renal failure, Turner’s syndrome and Prader-Willi syndrome, as well as for low-growth children born with intrauterine hypotrophy. Reimbursement does not cover treatment in adults except for patients with Prader-Willi syndrome who have already been treated in childhood. In the case of adults with an indication for GH treatment, they happen to take somatotropin by subcutaneous injection, which reduces their fat mass and increases muscle mass. The doctor determines the therapeutic dose of growth hormone individually for each patient – the price of one pack without reimbursement is several hundred zlotys. With early initiation of growth hormone treatment, it is possible that in the first year of therapy, the growth rate of the child is even from about 9 to almost 10 cm. Of course, all the rules of safe therapy must be observed – so the patient is under the continuous control of an endocrinologist and performs a full hormonal diagnostics. Taking recombinant growth hormone has its side effects on the body, such as diabetes, hypertension, insulin resistance, headaches, nausea, vomiting and visual disturbances. Growth hormone treatment is possible until the bone epiphysis is overgrown, and only in endocrinologically confirmed situations. For adults, the indication for hormone administration is the occurrence of such symptoms as an increase in abdominal fat, a decrease in muscle tissue and bone mineral density, and a decrease in the size and contractility of the heart.
There is a belief among some athletes and sports medicine practitioners that growth hormone pills and injections have a stimulating effect on weight loss, recovery, rejuvenation and muscle growth.
Effect of growth hormone in athletes
As we mentioned, growth hormone is sometimes popular in the world of sports. The inhibition of this hormone is influenced by, among other things, insufficient sleep duration, a poor diet with adequate amounts of micro- and macro-components, mainly protein, and pituitary adenoma. Growth hormone, on the other hand, is stimulated with physical activity, and is readily taken by bodybuilders because of its properties. Why? The effects of taking growth hormone include:
- increased muscle mass,
- reduction of body fat,
- converting fats released by the liver and muscles into energy,
- enabling you to perform more intense and longer workouts
- Growth hormone accelerates regeneration and healing of wounds – including those caused by burns,
- improves the condition of the skin, and prevents the formation of wrinkles,
- has a positive effect on mood and well-being,
- supports the synthesis of nucleic acids.
However, both insufficient growth hormone and excess growth hormone cause many diseases. And while these problems mainly affect children, abnormal GH norms in adults can also contribute to the symptoms of a variety of conditions. Adults who struggle with gigantism need to control it, as it has a huge impact on their heart – the muscle grows as a result of somatotropin. Athletes who decide to take growth hormone as a product that will help improve their physique must take into account a number of adverse effects of GH on the body. It should therefore be taken in safe doses, which are determined by a doctor. Excessive use of growth hormone can result in acromegaly, meaning enlargement of body parts, insulin resistance, diabetes, hypertension, excessive sweating, joint pain and excessive hairiness. It’s also worth considering that this supplementation is relatively expensive – with athletes opting for this supportive treatment, they should be under constant medical supervision to control GH levels at the right level.
