Growth hormone

Growth hormone (GH), also known as somatotropin (or as human growth hormone [hGH or HGH] in its human form), is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in human development. It is a type of mitogen which is specific only to certain kinds of cells. Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland.

GH is a stress hormone that raises the concentration of glucose and free fatty acids. It also stimulates production of IGF-1.

A recombinant form of hGH called somatropin (INN) is used as a prescription drug to treat children's growth disorders and adult growth hormone deficiency. In the United States, it is only available legally from pharmacies, by prescription from a doctor. In recent years in the United States, some doctors have started to prescribe growth hormone in GH-deficient older patients (but not on healthy people) to increase vitality. While legal, the efficacy and safety of this use for HGH has not been tested in a clinical trial. At this time, HGH is still considered a very complex hormone, and many of its functions are still unknown.

Growth hormone treatment

Growth hormone treatment refers to the use of growth hormone (GH) as a prescription medication—it is one form of hormone therapy. Growth hormone is a peptide hormone secreted by the pituitary gland that stimulates growth and cell reproduction. In the past, growth hormone was extracted from human pituitary glands. GH is now produced by recombinant DNA technology and is prescribed for a variety of reasons. GH therapy has been a focus of social and ethical controversies for 50 years.

This article describes the history of GH treatment, current uses and risks arising from GH use. Other articles describe GH physiology, diseases of GH excess (acromegaly and pituitary gigantism), deficiency, the recent phenomenon of HGH controversies, growth hormone in sports, and growth hormone for cows.

Medical uses

HGH deficiency in children

Growth hormone deficiency is treated by replacing GH. All GH prescribed in North America, Europe, and most of the rest of the world is a human GH, manufactured by recombinant DNA technology. As GH is a large peptide molecule, it must be injected into subcutaneous tissue or muscle to get it into the blood. Nearly painless insulin syringes make this less trying than is usually anticipated, but perceived discomfort is a subjective value.

Growth hormone 1

Somatotropin is a protein that in humans is encoded by the GH1 gene.

The protein encoded by this gene is a member of the somatotropin/prolactin family of hormones that play an important role in growth control. The gene, along with four other related genes, is located at the growth hormone locus on chromosome 17 where they are interspersed in the same transcriptional orientation, an arrangement thought to have evolved by a series of gene duplications. The five genes share a remarkably high degree of sequence identity. Alternative splicing generates additional isoforms of each of the five growth hormones, leading to further diversity and potential for specialization. This particular family member is expressed in the pituitary but not in placental tissue as is the case for the other four genes in the growth hormone locus. Mutations in or deletions of the gene lead to growth hormone deficiency and short stature.

See also

References

Further reading