Effects Of Human Growth Hormone

Human growth hormone (hGH) is a protein-based polypeptide hormone naturally produced in the body. Growth hormone (GH) is secreted by the anterior pituitary gland and affects the growth of all tissues by stimulating the release of insulin-like growth factors (IGFs). Growth hormone secretion is regulated by releasing hormones secreted from the hypothalamus. Additional input or stimuli that influence the secretion of GH include exercise, stress, low plasma-glucose levels and sleep.

HGH was originally obtained from an expensive, time-consuming method of extracting the hormone from the pituitary glands of cadavers. However, due to the success of genetic engineering, the hormone is readily available in mass quantities as of 2010.

Effects on Growth

As an anabolic agent, GH and IGFs stimulate tissue uptake of amino acids, the synthesis of new protein and long bone growth. When and how much the bones of a child grow depends on the levels of IGFs produced by the bone tissue and liver. IGFs promote cell division at the epiphyseal plate and enhance synthesis of the proteins needed to form new bone. An excess of GH during childhood is tied to gigantism, while a deficiency can cause dwarfism and requires administration of the hormone to regain normal position on the growth chart.

In addition to increased height, Magic Foundation suggests that children being treated with GH also show a decrease in body fat due to an increased metabolism. One negative side effect of the treatment in children is fasting hypoglycemia; however, this can be controlled with treatment (See References 4).

Effects on Muscle

Growth hormone, because of its role in protein synthesis, is used by some athletes in an attempt to increase muscle mass. GH increases protein synthesis in muscle; however, it is connective tissue protein or collagen that is increased rather than contractile protein. Therefore, strength gains do not parallel gains in actual muscle size.

Deficiency

According to the Mayo Clinic, adults with actual deficiencies of GH who receive injections can have an increased muscle mass and and bone density, as well as a decrease in body fat and increased exercise capacity. GH increases exercise capacity because it spares plasma glucose by opposing the action of insulin to reduce the use of plasma glucose, increases the synthesis of new glucose and promotes the mobilization of fatty acids from fat tissue.

Anti-Aging

"Beginning in middle age, the pituitary gland slowly reduces the amount of growth hormone it produces," according to the Mayo Clinic. This explains the characteristic decrease in muscle mass and increase in body fat seen with aging. While hGH is widely prescribed by physicians as an anti-aging drug, there is actually no conclusive evidence that hGH can prevent aging. However, there is ongoing research examining hGH as an anti-aging agent.