Synthetic human insulin was the first golden molecule of the biotech industry and the direct result of recombinant DNA technology. Currently millions of diabetic worldwide use synthetic insulin to regulate their blood sugar level. Synthetic insulin is made in bacteria and yeast.
Insulin is a peptide hormone produced by beta cells in the pancreas and its main function is to regulate carbohydrate and fat metabolismin the body. Insulin stops the use of fat as energy source by inhibiting the release of glucagon. It is a protein hormone composed of two chains of amino acids “A” and “B” linked together by two disulphide bonds. The A chain is composed of 21 amino acids and B chain of 30 amino acids, each arranged in uniquely ordered sequence.
Recombinant DNA technology
Recombinant DNA is the technique of combining the genes of different organism to form hybrid molecule. Scientist inserted synthetic genes carrying the genetic code for human insulin along with necessary control mechanism into E.coli bacterial strain which is a laboratory derivative of a common bacteria found in human intestine. Once inside the bacteria, the genes were “switched on” by bacteria to translate the code into A and B proteins chains found in insulin. The process is same as that used by bacteria to produce its own protein. When the cells produced sufficient amount of A and B proteins, they were harvested to isolate these proteins from the bacteria and purify it. The two chains were then combined chemically in laboratory to form complete insulin molecule which is identical to that produced by human protein.
Diabetes treatment using Insulin
Insulin therapy is important part of diabetic treatment. As insulin is a hormone that regulates the level of blood sugar (glucose) in body which would be otherwise toxic. When blood glucose level falls below a certain level, the body begins to use stored sugar as energy source through glycogenolysis which break down the glycogen stored in the muscles and liver into glucose which is then used as energy source. When insulin fails to function, diabetes occurs. In diabetic patient there is increase in blood glucose level, either because there is inadequate insulin production or body does not respond properly to insulin or both. In such condition, patients experience symptoms like frequent urination (polyuria), feel very thirsty (polydipsia), very hungry(polyphagia). There are two types of diabetes
Type 1 Diabetes – Where the body does not produce insulin.
Type 2 Diabetes – Where the body does not produce enough insulin or the cells in the body does not react to insulin (Insulin resistance).
Type 2 is most common type of diabetes and primarily depend on lifestyle and genetics and hence can be prevented by keeping normal body weight, regular exercise and following healthy diet.
Patient with Type 1 diabetes depend on external insulin (most commonly injected subcutaneously) as hormone is not produced by body. Whereas in Type 2 patients, insulin is given when other medicines fails to control blood glucose properly.
Thus Recombinant DNA technology played a very important role in providing insulin hormone to number of patients worldwide suffering from diabetes for controlling their blood sugar which otherwise if not controlled can lead to detrimental effects.