Growth hormone (GH) has only one approved medical use: the treatment of GH deficiencies in children and adults. Far greater public interest, however, has focused on its use to reverse the aging clock, to enhance athletic performance, and to breed livestock.
GH is produced by the pituitary gland, a pea-size structure located at the base of the brain. When obtained from human cadavers, pituitary supplies were understandably limited. However, since 1985, abundant supplies have been produced by recombinant DNA technology.
GH is needed for the normal growth of children and to maintain body fat, muscle, and bone in adults. Children with GH-deficiency typically receive six or seven injections each week for at least two years. Many children gain four inches the first year and three inches over the next two years, but not all respond satisfactorily.
Extravagant but scientifically unsubstantiated claims abound promoting the use of GH as an antiaging treatment. In a limited number of carefully controlled studies in healthy, elderly subjects, muscle mass increased and body fat decreased after administration of GH. However, no improvements were found in muscle strength, bone density, cholesterol levels, or other indexes associated with improved fitness.
The International Olympic Committee banned GH use in 1989. Nevertheless, there have been reports of athletes in power and endurance sports at the professional and amateur levels doping with this hormone. GH increases muscle mass and the speed at which injured tissue repairs itself, but there is no evidence that muscle strength is enhanced. Early studies are now underway to refine urine tests that can reliably differentiate between natural and injected GH.
Species-specific GH is commonly used to increase milk production by commercial dairy cows. However, its use to speed the rate of weight gain in cows—and, hence, beef’s time to market—has provoked international furor. The United States and Canada favor its use, while the European Union has banned the importation of treated meats since 1988, based on concerns that hormonal residues in meat may increase the risk of cancer and promote the earlier onset of puberty in girls.
SEE ALSO Biologic Drugs (1982), Human Insulin (1982), Epoetin (1989), Antiaging Drugs (2020).
Just as inadequate secretion of GH in childhood leads to individuals of small stature, excessive secretion results in persons whose height is significantly above average. According to ancient scribes, Goliath’s height was either 6' 9" (205.7 cm) or 9' 9" (297.2 cm). This David and Goliath fresco appears on a house wall in Regensburg in Bavaria, Germany.