A human growth hormone (HGH) is a hormone which is continuously secreted from the pituitary gland not only during a growth period but also all through life in a normal human. The human growth hormone was first extracted and purified from the human pituitary gland. Growth hormone secrets in a pulsatile manner throughout a 24-hour period. The pulsatile diurnal output of growth hormone is modulated by a pair of inner synergistic hypothalamus hormones, the growth hormone releasing hormone (GHRH) and growth hormone inhibiting hormone (GHIH) or somatostatin. Growth hormone stimulate growth of all tissues of the body that are capable of growing. Growth hormone is known to increase the rate of protein synthesis in the cells of the body, decrease rate of carbohydrate utilization in the cells of the body and increase mobilization of the fatty acids and use of the fatty acids for the energy. Proper human growth from infancy is contingent upon adequate growth hormone secretion. In normal development, HGH and the somatomedins are responsible for many manifestations of normal growth.
The growth hormone is associated with various events in the body, such as lipolysis, protein anabolism and osteogenesis. Therefore, in growth hormone-deficient patients, a lipolytic activity, an insulin-like growth factor I secreting activity, a protein synthesis stimulating activity, a bone metabolizing activity or the like are being decreased. Deficiency in growth hormone in children, it causes dwarfism. In adults, the acquired GH deficiency leads profound reduction in lean body mass and concomitant increase in total body fat, particularly in the truncal region. Decreased skeletal and cardiac muscle mass and muscle strength results in a significant reduction in exercise capacity. Bone density is also reduced. HGH supplementation has been shown to be an effective treatment for growth hormone deficiency and their related diseases states in humans. However, the source material for natural HGH (i.e., pituitary glands of cadavers) is limited. Recently, bioengineered HGH or recombinant HGH has been developed with identical characteristics as the natural HGH and removed the previous investigation limitations. Replacement therapy with recombinant GH (rhGH) has demonstrated favorable effects on most of the features of GH deficiency patients. Growth hormone may be administered by intramuscular or subcutaneous injection. Of these methods, subcutaneous injection may be preferred because it facilitates self-administration.
Growth hormone replacement therapy has been criticized because of side effects. Treatment with synthetic HGH may increase the risk of gigantism, an endocrine and metabolic disorder chracterized by abnormal size or overgrowth of the entire body or any of its parts. Other side affects include fluid retention, which is manifested by peripheral edema, joint swelling, and arthralgias, and carpal tunnel syndrome. Treatment of patients with growth hormone deficiency with recombinant human growth hormone has also been shown to affect the patients psychological well-being. |
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