Anatomy And Physiology

Anatomy Physiology

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In this article, I will discuss hormonal regulation of proteins metabolism in the body which are usually synthesized in the liver.  Especially notable here are the immunoglobulins, which are proteins that play a role in the immunology in the body.  They usually function as antibodies to fight pathogens inside the body. 

I will discuss the role of several hormones that are secreted to the bood circulation by the various endocrine glands in the body.  Some of these hormones exert a catabolic effect on proteins such as the hormone cortisol in which it stimulates the degradation of proteins into its amino acids constituents. 

Enzymes that are present in the gastrointestinal tract also have a catabolic or digestive role in the body in which proteins in the intestine and which are ingested in the diet are degraded to amino acids by specific enzymes that are secreted by the stomach cells and the pancreas.  A protein enzyme that digests proteins and which is secreted by the stomach cells is called pepsin.  On the other hand, protein enzymes that are secreted by the pancreas and which aid in the digestion of proteins in the intestine are called trypsin and chymotrypsin. 

 Proteins are polymers of amino acids in which are connected by peptide bonds between neigboring amino acids.  Usually the synthesis of proteins occurs in the process which is called translation.  In order for translation to occur it requires a nucleus in the cell which contains DNA and RNA and a genetic code.

 Synthesis of proteins requires a genetic code in which bases of DNA in sequence of three bases code for one amino acids that is then built on another amino acid on a cellular ribosome to build the proteins structure eventually.  The constructing of the sequence of amino acids in the polypeptide continues until the whole protein is synthesized.

 Protein synthesis in the body is affected by many hormones in the body which differ in their effect on protein metabolism.  Some hormones have anabolic effect on the proteins increasing the synthesis of these proteins in the body.  An example of this type of hormone is growth hormone which is synthesized and secreted to the blood circulation by the anterior pituitary gland.

 This hormone has many other effects on the body in addition to its anabolic effect on protein synthesis.  The presumed mechanism of action of this hormone on increasing the amount of proteins in the body is to stmulate the entry of amino acids into the cells by a mechanism similar to that of insulin effect on glucose.  Thus making large amount of amino acids available for the cell in the translational process of protein synthesis.

 Also another presumed function of this hormone is that it accelerates the process of DNA and RNA transcription in the cell.  Growth hormone does not have a specific target organ to act upon but instead it has a universal effect on all body tissues causing in general growth in all parts of the body.  It lets the body develops tall structure if it is excessive in the blood while its deficiency causes dwarfism.

 Also the hormone insulin has an anabolic effect on proteins increasing the synthetic capacity inside the cell of proteins.  It is thought that insulin increases the uptake of amino acids by the cells of the body.  This effect is similar to its effect on  promoting the entry of glucose into the cells.  Thus increasing the rate by which proteins are synthesized in the cell. 

 Cortisol is another hormone which is secreted by the adrenal cortex has a catabolic effect on proteins in the body increasing its degradation.  Thus making large amount of amino acids available in the blood for proteins synthesis and for other processes such as gluconeogenesis. 

 The other hormone which is the steroid hormone testosterone has a strong anabolic effect on proteins synthesis in the body especially notable here is the proteins of muscle tissue that participate in the contraction process of these muscles.  Testosterone analogues are often used by athletes in order to develop muscles in the body.  This is possible due to its ability to deposit proteins in the body tisues including the body muscles.

The female hormone estrogen has similar anabolic effect on proteins of the body causing anabolic effect but to a lesser extent than that for testosterone. 

More about this author: Tarek Musslimani

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