Growth hormone.
Growth hormone, called somatropin or somatotropin  as well, is a polypeptide hormone produced and secreted by the somatotrope cells, located in the anterior area of the pituitary gland. This gland is also called hypophysis and it is located in the lower part of the brain just underneath the hypothalamus. Pituitary gland is divided in two sections; the anterior and the posterior lobe and it is responsible for the synthesis, storage and release of a large number of hormones. Among them, growth hormone is included. The latest regulates and stimulates growth and cell reproduction in humans and other vertebrate animals. If the somatotrope cells fail to develop and function properly, a condition occurs which is referred to as deficiency in growth hormone. This medical problem results in dwarfism. The latest is a dysmorphic condition in which, although the proportions are correct, the size of the body is very small. Deficiencies in growth hormone are classified as acquired which develop overtime, and congenital which are present at the very beginning of a person’s life.
Properties of growth hormone.
The effects of growth hormone on the body tissues can, generally, be defined as anabolic ones. Growth hormone is a protein and interacts with specific receptors on the surface of cells.
 The presence of excessive amounts of growth hormone results in a chronic metabolic disorder called acromegaly. This condition involves the gradual enlargement of body tissues, including the bones of the face, jaw, hands, feet and skull.
Although height increase is the best macroscopic known effect of growth hormone, it contributes to a lot of other metabolic functions, as well. For instance it boosts calcium retention and therefore improves the mineralization of bones.
Growth hormone promotes protein production and development of many different organ systems, leading to a positive nitrogen balance.
Growth hormone improves immunity and participates in homeostasis. Growth hormone also contributes to the maintenance, control and proper function of pancreatic islets which produce hormones responsible for control of blood glucose, such as insulin and glucagon.
Growth hormone appears to help in lipolysis which, in turn, results in moderate reduction of body fat and the release of fatty acids in the bloodstream.
Growth hormone is essential for the increase of bone size and muscle mass. In fact, this is the reason why it is very popular among bodybuilders..
Growth hormone excess.
A pituitary tumor is the most common cause of growth hormone excess. Such tumors, called adenomas, develop gradually and increase the synthesis leading to abundance of the hormone.
If the growth hormone excess is neglected and remains untreated, it can result in acromegaly. Other problems related to development of pituitary adenoma and acromegaly may include headaches, impaired sight, neuropathy, neuralgia, muscle weakness, deficiency of other pituitary hormones, insulin resistance, type 2 diabetes and decreased sexual response and function.
Pituitary adenoma occurs in childhood very rarely. If it happens, a condition called pituitary gigantism is developed and involves excessive, abnormal body growth. In most of the cases, symptoms get apparent and pituitary adenoma is diagnosed within the fifth decade of age.
The most prominent treatment of growth hormone excess is the surgical removal of the pituitary tumor. Under certain circumstances, antagonist substances or radiation may be chosen to control growth hormone function or to make the adenoma to shrink.
Growth hormone deficiency.
The most common causes of growth hormone deficiency include hereditary factors, congenital deformations of certain parts of brain, such as hypothalamus or pituitary gland and damage of the latest due to injury or disease. The malfunction of the pituitary gland leads to growth hormone deficiency.
Acquired growth hormone deficiency can occur at any age and the symptoms may include inadequate body growth, reduced muscle mass, bone density and persisting fatigue. Growth hormone deficiency may result in cardiovascular disease.
Synthetic type of growth hormone is used as replacement therapy. Although the benefits vary, in most of the cases they are very satisfactory. The changes that may be achieved include the increase of muscle mass, bone strength and the reduction of body fat.
Side-effects and risks of treatment are quite rare, when growth hormone is provided in replacement doses to deficient children and adults. Risks are uncommon, even when the medicine is prescribed in pharmacological doses for other reasons.
Supplements of growth hormone are used as bodybuilding aids and under certain circumstances, to help in weight loss in obese people.
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