The role of human growth hormone in your body
Human growth hormone (hGH or GH)—also known as somatotropin—is a protein that is important not only during childhood growth but throughout adulthood. It is produced by the pituitary gland, which is also known as the "master gland" because it secretes many hormones that control the actions of other glands. A part of the brain called the hypothalamus sends signals to the pituitary gland to produce growth hormone, which then travels through the bloodstream to function in other parts of the body.
Scientific research usually focuses on the role of growth hormone in the growth process, but its contribution to adult metabolic processes (the physical and chemical body processes that maintain life) is also crucial.
Learn more about how human growth hormone works by viewing an animation now.
Growth hormone and growth
Growth is affected by more than hormones. Good nutrition and a child's general health are important factors in normal growth.Likewise, growth hormone isn't the only hormone that affects the growth process. Other pituitary hormones—thyroid-stimulating hormone, adrenocorticotropic hormone, luteinizing hormone, and follicle-stimulating hormone—affect growth indirectly by acting through other glands. Although many hormones can influence growth, GH is the major growth regulator in the body.
The primary job of growth hormone is to cause bones and other body tissues to grow. For bone growth, it directly stimulates the areas of bones known as epiphyseal growth plates, which are responsible for bone elongation. In addition to stimulating growth, growth hormone also causes growth indirectly by triggering the release of a protein called insulin-like growth factor-I (IGF-I) from tissues throughout the body. IGF-I stimulates the growth of bone, muscle, and other body tissues in response to growth hormone and, in turn, regulates GH release from the pituitary gland. Growth hormone also contributes to proper bone density. This mechanism, in conjunction with other complex body processes, maintains growth from infancy through adulthood.
Growth hormone and metabolism
The importance of growth hormone doesn't diminish once adulthood is reached and bone growth stops. Growth hormone also helps regulate metabolism (the chemical processes by which the body turns food into energy, tissue, or waste products) in a number of ways—transporting molecules, conserving sugars, building proteins (including muscles), and breaking down fats. Not only is it vital to maintaining healthy body composition, it also contributes to proper bone density, and ratios of "good" to "bad" cholesterol.
Growth hormone deficiency
When the body doesn't make enough growth hormone to keep a child's bones growing at the proper rate, a condition known as pediatric growth hormone deficiency (PGHD) results. When an adult doesn't produce enough growth hormone, he or she has adult growth hormone deficiency (AGHD).
References
Guyton AC, Hall JE. Textbook of Medical Physiology. 9th ed. Philadelphia, Pa: WB Saunders; 1996.Lifshitz F, ed. Pediatric Endocrinology. 4th ed. New York, NY: Marcel Dekker Inc; 2003.
Nutropin AQ [product monograph]. South San Francisco, Calif: Genentech Inc; 2002.
Wilson JD, Foster DW, Kronenberg HM, Larsen PR, eds. Williams Textbook of Endocrinology. 9th ed. Philadelphia, Pa: WB Saunders; 1998.
