Human growth hormone (HGH) or somatotropin, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration. HGH is synthesized, stored and secreted in the pituitary brand.
The History of Growth Hormone Therapy
In the late 19th century the importance of the pituitary gland for growth was recognized. However, growth hormone therapies were first applied to severely GH-deficient children and adolescents only by 1956. At that time, there was limited availability of growth hormones, so it was awarded on the basis of clinical research protocols approved by the National Pituitary Agency (NPA). From 1963 to 1985, the NPA oversaw almost every GH treatment in the United States. During this period, the NPA supplied GH extracted from the human pituitary gland to treat the severe Growth Hormone Deficiency of approximately 7,700 American children and 27,000 children worldwide.
However, after four young American adults who received GH treatment developed Creuzfeldt Jacob Disease in 1985, distribution and use of GH extracted from the pituitary gland had been discontinued. Since then, Genentech’s synthetic methionyl GH has been approved by the FDA for the treatment of severe GH deficiency.
How Can Growth Hormone Help Children and Adolescents Grow and is it Safe?
In children and adolescents, it stimulates the growth of bone and cartilage. In people of all ages, GH boosts protein production, promotes the utilization of fat, interferes with the action of insulin, and raises blood sugar levels. Metabolic effects of growth hormone are divided into direct effects of growth hormone and indirect effects through Insulin-like Growth Factor-1(IGF-1). Protein accumulation is mainly caused by the direct action of growth hormone, and additionally through IGF-I production(indirect action). The growth hormone is beneficial to the heart and blood vessels as it leads to muscle gain and decreases total cholesterol and LDL cholesterol, the main cause of arteriosclerosis.
Fatty tissue is particularly well known as a site of action of growth hormone. The growth hormone acts as an anti-insulin and lipolytic agent, increasing free fatty acids and glycerol and inhibiting fat formation. Growth hormone deficiency can also reduce body fat in patients with growth hormone deficiency.
There is a difference between the direct effect of growth hormone and the effect of indirect action via IGF-1. GH has a diabetogenic action that decreases insulin sensitivity, increases post-prandial hepatic glucose release, and reduces glucose uptake, leading to glucose intolerance. This is a condition in which blood glucose is maintained at a high level due to abnormally degraded glucose processing ability of a living body. IGF-1 causes hypoglycemia, as opposed to growth hormone. In addition to increasing glucose uptake in muscles, IGF-1 also increases glucose secretion in the liver.
There is also a view that growth hormone helps prevent aging. In 1990, Rudman and colleagues reported the effects of 6 months of Human growth hormone administration on the body composition of 12 older men (aged 61-81), and highlighted the benefits of growth hormone in preventing aging. The administration of growth hormone in older men resulted in a 4.7-kg increase in lean body mass, a 3.5-kg decrease in adipose mass, and an increase of 0.02 g per square centimeter in lumbar-spine density; systolic blood pressure and the fasting glucose concentration increased significantly. The study was not double-blind (there was a control group consisting of nine men who received no treatment); there were no assessments of muscle strength, exercise endurance, or quality of life. This study is the basis for claims that growth hormone reverses aging.)
Side Effects of Growth Hormone
Significant side effects of growth hormone administration on metabolic effects have not been shown. However, infusion of HGH can cause the following side effects: Tunnel syndrome, arthralgia and muscle pain, increased cholesterol levels, vomiting, constipation, headache, skin rash, dizziness, etc.
Arthralgia and myalgia are more likely to occur in adults than in children. In the case of headaches caused by increased intracranial pressure, symptoms stop when treatment is stopped. Meanwhile, growth hormone can affect insulin and raise blood sugar levels. This can result in type 2 diabetes or worsen the patient’s existing diabetes.
Leukemia has been reported after administration of growth hormone to patients with microsomia due to pituitary abnormalities. There also have been reports of recurrence of brain tumors in patients with growth hormone. Therefore, care should be taken in administering growth hormone via injection.
Lack and Excess Growth Hormone
Lack of growth hormone causes disease, but excess growth hormone is also a risk of the disease. Excess growth hormone causes abnormal growth in tissues since growth hormone stimulates the growth of bones, muscles and many other organs. This is known as a disease called gigantism or acromegaly. Excessive growth hormone secretion is mostly caused by a benign tumor of the pituitary gland called adenoma. This commonly causes problems with visual impairment, weakness, and heart failure. To treat overproduction of growth hormone, surgery, radiation therapy, and drug therapy should be combined.
Injecting growth hormone does not necessarily increase height. The FDA allows the injection of synthetic human growth hormone only for certain uses. For example, when tunnel syndrome, Prader-Willi syndrome, or when HGH (Human Growth Hormone) is inadequate, injection of synthetic growth hormone is allowed. In the case of adults, growth hormone supplements are only approved when there is a growth hormone deficiency due to the pituitary gland or brain tumor, or when certain diseases such as AIDS are present. Since the efficiency and safety of growth hormone have not been fully understood, further research on the side effects of growth hormone supplementation is needed.
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- Somatropin Side Effects, Drugs.com
- Gigantism and Acromegaly, MERK MANUAL Consumer Version (Ian M. Chapman, MBBS, PhD, University of Adelaide, Royal Adelaide Hospital)