Discovery Of The Somatotropin Biology Essay

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In the 1920s, Somatotropin was first characterized by Evans and Simpson when they presented the growth-promoting effects in rats with a substance from anterior pituitary gland. And they also found an alkaline extract of the anterior pituitary gland decreased carcass fat in rats. This found out that the substance was crucial in stimulated growth rate. Therefore this substance was being referred to as "growth hormone" (Evan H. M., Simpson M. E., 1931). After the discovery of Evan and Simpson, the growth hormone research was starting to be concerned. It was not until 1945, Li et al. had isolated growth hormone from anterior pituitary (Li C. H., Evans H. M., SIMPSON M. E., 1945). They conducted an experiment to show that the rough preparation of growth hormone by copying the effect of the alkaline pituitary extract had on carcass fat in rats (Li C. H., Evans H. M., SIMPSON M. E., 1948). Even the growth hormone preparation by Li et al. was not pure, but it had provided the foundation on study of growth rate. And this also improved the purification schemes for future development.

After the growth hormone preparation discovered, number of studies to evaluate the effects of pituitary preparations of porcine growth hormone (pGH) on growth and carcass composition of pigs were conducted. But those studies are indefinite probably because the Growth hormone preparation was not pure. In early of 1980s, the studies of the effects of growth hormone in domestic livestock was investigated, but it was not apply in commercial application due to the amount of growth hormone that could be extracted from the slaughtered animals' pituitary glands was insufficient to influence commercial production (Young F. G., 1947).

However, in early 1980s the breakthrough of biotechnology enabled Growth hormone to be produced by recombinant DNA technology. The availability of large quantities of recombinantly derived pGH permitted extensive investigations to be conducted. Those studies showed that growth rate, carcass composition, and productive efficiency of 30 to 77 days growing pigs with daily administration of a maximally effective dose of pGH were improved obviously (Etherton T. D., 2000).

What is Somatotropin

Somatotropin is also known as growth hormone, it is single chained polypeptide hormone made up of 191 amino acids which take place in stimulate growth, cell reproduction and regeneration. Growth hormone is produce naturally in human body, it synthesized stored and excreted into the blood by the somatotropic cells of the anterior pituitary gland.

Regulation of growth hormone is controlled by neurosecretory nuclei of the hypothalamus. These cells produce two kind of neuroendocrine hormones, which are growth hormone releasing hormone (GHRH) and somatostatin into the hypophyseal portal venous blood surrounding the pituitary. The GHRH acts as atimulator while somatostatin acts as inhibitor which controlling the balancing of growth hormone. The growth hormone is synthesized and secrete by somatotropic cells in the anterior pituitary gland, and this response is stimuli by hypothalamus.

Growth hormone was very important substance for regulating human body functions include stimulates cell growth, increases healing and recovery from exertion, calcium retention in bones, increases bone size, stimulates cell activity, increases use of fats in the body, increases protein formation, increases sugar absorption by the cells of the body, stimulates immune system, increases metabolism and so on.

The growth hormone level in children is generally high, and during puberty, adolescence having highest level of growth hormone. After puberty, the level of growth hormone secretes will decrease but remain in a substantially lower level. Human body need growth hormone to repair all of the damage cells from the surrounding environment to prevent cellular deficit which means the human body couldn't produce correspond new body cells as damage cells to keep human body function optimally. Cell deficit commonly appear on elder people, which make their skin becomes wrinkled and discolored, hair grays, posture weakens and muscle tone and body mass decrease.

Somatotropin is also playing important role in some secretion of hormones. For examples, like testosterone, estrogen, progesterone and insulin-like growth factor 1 (IGF-1). IGF-1 is a hormone having similar in molecular structure with insulin, it play an important role in childhood growth and continues to have anabolic effects in adults.

The application of somatotropin was very wide. It can use for anti aging purposes, or to boost athletic performance. The easiest way to improve somatotropin level in human body is injecting synthetically manufactured hormones. Older persons are seen to be full of vigor and reduce some aging affection after injecting somatotropin, while athletes commonly use somatotropin to improve strength and performance. Somatotropin can't be taken orally because it will be digested.

Another application of somatotropin is treatment of growth hormone deficiency. Turner syndrome, Noonan syndrome, short bowel syndrome are some examples for growth hormone deficiency. The common causes of growth hormone deficiency including genetic conditions and congenital malformations.

Like every drugs, somatotropin have some side effect too. For example, hypoglycemia, acromeglia, carpal tunnel syndrome, extended belly, joint pain and so on. Furthermore, immune response against somatotropin also occurred.