Insulin Research Paper

Insulin plays a critical role in integration and regulation of carbohydrates and lipid metabolism.
Insulin and regulation of carbohydrate metabolism
Insulin is a peptide hormone which is secreted by the pancreatic beta-cell that present in the islet of Langerhans. It is a protein that function to regulate the metabolism of carbohydrates, fats and protein and also utilize of energy from the ingested nutrients especially glucose. Foods that consist of carbohydrates are converted into glucose during digestion and is then absorbed into the bloodstream, this absorption will affect the glucose concentration in our body. Increasing of blood glucose level triggers pancreas to release insulin into the bloodstream which stimulates cells to take up glucose.
Muscles and body tissues in our body consume glucose as energy source to undergo glycolysis and cellular respiration (Drury 1940).
Insulin will stimulate liver to store excess glucose as glycogen and also fatty acid which stored in adipose tissue. It activates the enzyme hexokinase, which phosphorylates glucose, trapping it within the cell and hence block the activity of glucose-6-phosphatase (Plum, Belgardt & Brüning 2006). Insulin will restrain fuel mobilization and breakdown of glycogen are blocked. Hence, causes the glucose to decrease gradually. However, the blood glucose will go back to the basal value. This is due to the secretion of basal insulin by pancreas to regulate the blood glucose level back to normal. Negative feedback organism occurs when blood glucose higher than normal, beta cells secrete insulin to blocks the production of glucose and move glucose from blood into cells to be used for energy. Glycolysis and ATP production will increase, which will close K+ channels and causes a depolarization of the
cell membrane. Hence, Ca2+ channel is open and causes the release of insulin to regulate blood glucose level to the normal level. (Saltiel & Kahn 2001)
Insulin and regulation of lipid metabolism
Insulin stimulates synthesis of fatty acids and glycogen in the liver.
However, further synthesis will stop when glycogen increase has reached to high levels which is approximately 5% of liver mass. Hepatocytes will convert any extra glucose into pathways when the liver is saturated with glycogen in order to synthesize fatty acids which are exported from the liver as lipoproteins (Postic & Girard 2008). The lipoproteins are ripped apart in the circulation to produce free fatty acids for other tissues such as adipocytes to synthesize triglycerides. Besides, breakdown of fat in adipose tissue will also be prevented by preventing the intracellular lipase that hydrolyses triglycerides to produce fatty acids (Wang et.al 2003). Insulin transfer glucose into adipocytes which can be utilized to synthesise glycerol in adipocytes (Jungas 1970). This glycerol together with the fatty acids carried from the liver, is utilised to synthesize triglyceride in the adipocyte. Insulin is associated in build-up of triglyceride in fat cells by these mechanisms and has a fat-sparing effect from a whole body perspective. Insulin triggered build-up of fat in adipose tissue indirectly and stimulate most cells to preferentially oxidize carbohydrates rather than fatty acids for
energy.
To maintain a balance between carbohydrate and lipid level in our body, we should consume of balance diet which consists of protein, carbohydrates and also fats. And also, exercising regularly will also help to maintain a balance between carbohydrate and lipid level