Human Growth Hormone (hGH) is produced in the pituitary gland of humans, and the hormone is secreted throughout a person's lifetime. It promotes growth in children and plays an important role in adult metabolism.
It was first isolated in 1956 and its structure was identified in 1972. Until the mid-1980's the only source of hGH was from pituitary glands collected post mortem. Today hGH is available in larger quantities through the technique of genetic engineering and, consequently, a number of conditions apart from the classical growth hormone insufficiency can be treated.
Growth hormone insufficiency is a condition caused by a deficiency of natural growth hormone. Without treatment, e.g. boys typically reach a height of 130 cm at the age of 18, compared with a normal height of 162 cm. If treatment with growth hormone is initiated at an early stage, a final height close to normal can be obtained.
Turner's Syndrome is a genetic defect associated with short stature. Turner's syndrome affects girl's only. It is caused by a defect of one of the x chromosomes.
Chronic Renal Insufficiency growth retardation is often seen as a clinical manifestation of progressive chronic renal insufficiency in children. Since dialysis and transplantation sustain the lives of more children with end-state renal failure, short stature has become a prominent problem.
Growth hormone deficiency in adults is either due to a pituitary surgery or onset of growth hormone insufficiency during childhood. In adults, secretion of growth hormone regulates a number of metabolic processes.
Human Growth Hormone is a naturally occurring substance in the human body which is secreted by the pituitary, the master gland of the body located in the endocrine system. Growth Hormone is important for a number of reasons, in older individuals, it can slow down and in many cases even reverse the aging process. Aging is now considered a disease and not just a normal occurrence which goes unchecked. Traditionally, it has been used in Europe and the United States for approximately 15 years with very gratifying results. It has previously been available by injection only and since injections can cost between $4,000 and $20,000 a year, only the wealthy have been able to afford this treatment.
Growth hormone declines with age in every animal species that have been tested to date. In humans, the amount of growth hormone after the age of 21 to 31 falls about 14% per decade, so that the total 24-hour growth hormone production rate is reduced in half by the age of 60. In numerical values, we produce on a daily basis about 500 micrograms at 20 years of age, 200 micrograms at 40 years, and 25 micrograms at 80 years old.
The easiest way to measure growth hormone in the body is by measuring plasma IGF-1 levels. Under 350 IU is considered evidence of deficiency. Between the ages of 20 to 40 years, less than 5% of healthy men have less than 350 IU per liter of IGF-1 levels. But after 60, 30% of apparently healthy men have this low amount. And after age 65, about half the population is partially or wholly deficient in growth hormone.
Total daily hGH secretion declines in humans with increasing age. "Elderly" levels are reached by age 35-40.
Insulin-like growth factor, or IGF-1 is actually safer and just as potent as growth hormone by itself. The problem in the past with human Growth Hormone has been that it is broken down in the stomach by the bile acids and was not absorbed into the system. Now, a substance that stimulates IGF-1 called Pro hGH is available orally.
There are many hormones which work with growth hormone and can help it work more effectively in the body. They are Estrogen, Progesterone, Melatonin, DHEA, and Thyroid Hormone.
Estrogen: Slows the loss of minerals from bones and increases blood clotting, however, it decreases oxygen metabolism to the cells and is known to be a factor in breast and uterine cancer.
Progesterone: Essential for the metabolism of glucose and the proper formation of bones, progesterone stimulates the production of new heart cells in the body and suppresses cancer growth.
Melatonin: Produced naturally in the brain by the pineal gland, it stimulates the production of growth hormone and reduces free-radical damage. Melatonin has the ability to stabilize the body's biological rhythms and stimulate the immune system.
DHEA: One of the most powerful hormones for improving brain function, DHEA (dehydroepiandrosterone) is the most abundant hormone found in the bloodstream. The function of DHEA is to serve as a precursor for all other hormones in the body by supplying the body with what it needs to maintain an optimum balance of all hormones that regulate metabolic functions. As we age, the level of DHEA declines dramatically. Low levels of DHEA are linked to such conditions as diabetes, obesity, high cholesterol, heart disease, arthritis, and many other symptoms associated with aging.
Thyroid Hormone: Thyroid hormones regulate metabolism in every cell. Without these hormones the body's altered metabolism can result in chronic fatigue, or depression. Thyroid hormones can also be extremely useful in overcoming decreased metabolism often associated with prolonged obesity. However, there is concern for potential side effects, therefore they should only be prescribed by a physician.
Somatotropin: This test requires a blood sample. The patient should be fasting (nothing to eat or drink from midnight the night before the test). Stress and/or exercise increases hGH levels, so the patient should be at complete rest for 30 minutes before the blood sample is drawn. If the physician has requested two samples, they should be drawn on consecutive days at approximately the same time on both days, preferably between 6 am and 8 am.
Somatomedin C: This test requires a blood sample. The patient should have nothing to eat or drink from midnight the night before the test.
Growth hormone stimulation: This test requires intravenous administration of medications and the withdrawal of frequent blood samples, which are obtained at 0, 60, and 90 minutes after injection of arginine and/or insulin. The patient should have nothing to eat or drink after midnight the night before the test.
Growth hormone suppression: This test requires two blood samples, one before the test and another two hours after administration of 100 g of glucose solution by mouth. The patient should have nothing to eat or drink after midnight, and physical activity should be limited for 10-12 hours before the test.