The Way that HGH Works - Essay Example

Human Growth Hormone Human growth hormone, also known as HGH or somatotrophin, is significant to normal human and animal growth patterns. The purpose of this paper is to discuss HGH, its importance, its functions, and diseases which can develop which involve human growth hormone. The fundamental function of HGH is the stimulation of cell production and the regulation of multiple physiological functions. One example of its function is that it is crucial to the process of differentiation of muscle and bone cells. It is also critical in the process of growth. In humans, HGH is secreted throughout the life span of the individual, not just during growth periods. In children, however, GH is responsible for multiplying and dividing chondrocytes. These cells are located in the cartilage and are responsible for the growth of the long end of bones. Additionally, GH is important to the synthesis of IGF-1 (insulin-like growth factor 1, very similar to proinsulin). GH is often found in the liver where IGF-1 is produced. The way that HGH works is similar to the way that many other hormones and amino acids function, through a binding process to plasma membrane receptors specific to HGH, “ Growth hormone (GH) signals through its receptor GHR to stimulate proliferation”(Gough, 2008). These receptors are known as GHR or growth hormone receptors. Its unique structure composed of 4 helices allows it to bind quite specifically to the GH receptors of appropriate plasma membranes. The ability to bind to GHRs appears in two different binding epitopes. The GH will bind to two identical receptors at the domain interface of the receptor on an extra cellular level. HGH is essentially 191 amino acids formed together into a single chain polypeptide: “There are two known types of human growth hormone derived from the pituitary gland: one having a molecular weight of about 22,000 (22K or kDa hGH) and the other having a molecular weight of about 20,000 (20K hGH). 20K HGH is made in the pituitary and secreted into the blood. 20K HGH has an amino acid sequence which corresponds to that of 22K hGH consisting of 191 amino acids except that 15 amino acid residues from the 32nd to the 46th inclusive from the N-terminal of 22K hGH are lacked” (HGH Product Research, 2008). It is made, stored, and secreted within the somatotroph, “In the normal person, a fall in blood glucose within the physiological range and without production of hypoglycemia also elicits GH secretion” (Johnson et al, 1985). The somatotroph can be found in the lateral wing of the anterior pituitary gland. When we refer to HGH as somatotrophin we are specifically referring to GH which has been produced from recombinant DNA. One can also refer to this type of GH as hGH or rGH (recombinant growth hormone). HGH can be genetically engineered for the treatment of certain diseases. The genetic information which provides the code for naturally produced growth hormone is found on chromosome 17. The loci is on the q arm at q22-24. There are two genes in particular that code for growth hormone on chromosome 17; they are known as hGH-N and hGH-V. The gene which codes for human placental lactogen (hpl) is also significant in growth hormone production. HGH is actually quite similar to human chorionic somatotrophin, also referred to as placental lactogen. As mentioned earlier, GH is involved in a myriad of physiological activities. These activities include anabolism of proteins, lypolysis and osteogenesis (bone formation). In patients with disorders or disorders involving GH, these functions are decreased, usually causing a wide variety of symptoms and problems for the individual. In those with GH deficiencies, bone metabolic activity, lypolitic activity and protein synthesis, decrease. One result of this type of deficiency is obesity or a build of subcutaneous fat due to an inability to properly break down lipids (fats). The deficiency of GH is not the only possible adverse complication that can occur in humans. An over production of HGH is also quite detrimental to the body. One disease that often occurs as a result of over production of HGH is a tumor formation located in the pituitary. This type of tumor is often composed of somatotroph cells stemming from the anterior pituitary. Typically the adenoma (tumor caused by over production of HGH in pituitary) will grow slowly for a long period of time. Symptoms will present once the tumor is large enough to place pressure on the optic nerves and the cranium causing headaches and changes in vision. In individuals with overproductions of HGH, symptoms such as lowered sexual appetite, carpal tunnel syndrome, thickening of the bones (particularly in the jaw and fingers) as well as pressure to nerves may occur. Additionally, patients suffering from over production of HGH may experience insulin resistance and diabetic symptoms (in rare occasions, individuals with over production of HGH will suffer from type 2 Diabetes). Similarly, individuals may also suffer from a lack of sufficient production of HGH. This can result in individuals being of small stature or in specific types of dwarfism. One such disease is known as Hypopituitary Dwarfism. This disease is seen in childhood where the individual is not able to produce adequate amounts of HGH. This particular disease is one which may be treated with hGH from other humans. Unfortunately, utilizing growth hormone from other organisms is not at all effective in treating this disease. In the past, scientists have attempted to use growth hormone from human cadavers. This was an effective method albeit extremely expensive. The process required the use of 70 cadavers over the period of a year in order to treat one child suffering from this type of dwarfism. Later researched showed that by cloning and expressing the hGH gene, one could effectively produce hGH for treatment in those with HGH deficiencies. (Weaver, Hendrick, 1997). It can be said that HGH is one of the hormones that directly and drastically effects the way in which a person looks. HGH is directly responsible for how tall or short we are. We have discussed symptoms of dwarfism as well as the affect on the individual’s height who suffers from such a deficiency. In individuals who are overproducers of the hormone however, a condition known as being a “pituitary giant” can also result. This is not simply a condition of being overly tall in stature. These individuals often suffer from weak organs, particularly the heart. In optimal conditions, an individual produces a normal amount of the hormone in order to regulate normal growth patterns, normal insulin production as well as normal homeostatic and immune system regulation. (Mader, 1998). In some cases, athletes use GH to increase performance in professional competitions, “Athletes’ use of growth hormone is banned by the International Olympic Committee, Major League Baseball and the National Football League. It is also illegal to distribute the drug for the purposes of sports enhancement in the United States. Despite this, athletes have been accused in recent months of taking the drug to boost their strength and performance. One attraction to growth hormone as an athletic enhancer is that it is difficult to detect”(Science Daily, 1995-2008). Works Cited: Primary Sources: Feinberg, MS, Scheinowitz, M., Laron, Z. (2000) Echocardiographic Dimensions and Function in Adults With Primary Growth Hormone Resistance, Pubmed.gov, retrieved 18 June 2008 from website at: http://www.ncbi.nlm.nih.gov/pubmed/10955379 Gough, Nancy R., (2008) LYN For Growth Hormone Receptors, Science Signaling 10 June 2008 vol 1 issue 23, retrieved 18 June 2008 from website at:http://stke.sciencemag.org/cgi/content/abstract/sigtrans;1/23/ec211 HGH Product Research, (1998) Human Growth Hormone (HGH), retrieved from website 18 June 2008 at: http://www.hghhormonesupplements.com/human-growth-hormone.php Johnson, DG., Davies, R.R., Prescott, RW., (1985) Regulation of Growth Hormone Secretion in man: Review, JR Soc Med 78(4) pp. 319-327, retrieved 18 June 2008 from website at: http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=1289683&pagei ndex=2#page ScienceDaily, (March 23, 2008) No Evidence Growth Hormone Boosts Athletic Performance, Review Suggests:, Science Daily , retrieved 18 June 2008 from website at: http://www.sciencedaily.com/releases/2008/03/080320132224.htm Secondary Sources: Mader, Sylvia S. (1998) Biology: Sixth Edition, McGraw-Hill Publishing, New York. Weaver Robert F., Hendrick, Phillip W. (1997) Genetics: Third Edition, McGraw- Hill, New York. ,(2006) Somatatropin: About Human Growth Hormone, retrieved 18 June 2008 from website at: http://www.somatropin.net/ Essay Outline: 1. HGH Defined A. Functions of HGH B. HGH gene loci and GHR 2. HGH Diseases and Abnormalities A. Deficiencies in HGH Production B. Overproduction of HGH C. Synthetic Use Read More