Alternative name:
Somatropin
Description
Human growth hormone (GH) or somatropin is a polypeptide hormone secreted by the anterior pituitary gland. Normal growth in children is dependent upon GH. Growth hormone affects the growth of almost every organ and tissue in the body. It has been shown to cause retention of nitrogen, and an increase in protein synthesis, producing an anabolic effect.
Growth hormone also stimulates the mobilization of lipids from adipose tissue and increases their oxidation as a source of energy, thus sparing muscle glycogen. Overproduction of GH before growth is complete can result in gigantism. If it occurs after cessation of growth when the epiphyses have closed, it causes acromegaly. Acromegaly is characterized by an increase in the size of the skull with prominent cheekbones and a protruding jaw and the broadening of the hands and feet. Facial features become coarse as a result of increased growth of subcutaneous tissues.
There is some evidence suggesting a relationship between long-term administration of GH and the development of acute leukaemia, with the incidence of leukaemia in GH-treated patients representing a twofold increase over the expected rate. The use of GH has also been linked to the development of osteoporosis.
A number of deaths from CJD in patients who had received GH extracted from human pituitary glands resulted in the suspension of the distribution of pituitary-derived GH. Synthetic preparations of GH are now available that are free from contamination with the CJD virus. However, because of the long incubation period of this virus, cases of infection are still being reported in patients who had received pituitary-derived GH many years ago.
Athletes using GH to either increase their size and strength or their ultimate height, depending on the maturity of the user, are at risk of developing the clinical syndromes gigantism or acromegaly.
Reported side-effects have included skeletal changes, enlargement of internal organs including cardiomegaly, development of diabetes, arthritis, impotence and inflammation and pain at injection sites. One of the most commonly reported adverse effects of GH in athletes is the thickening and coarsening of the skin.