Production of Insulin

Insulin is a peptide hormone, secreted by the pancreas, that regulates glucose metabolism in the body. Insufficient production of insulin or failure of insulin to stimulate target sites in liver, muscle, and adipose tissue leads to the serious metabolic disorder known as diabetes mellitus. Diabetes afflicts millions of people worldwide. Diabetic individuals typically exhibit high levels of glucose in the blood, but insulin injection therapy allows diabetic individuals to maintain normal levels of blood glucose. 

This is a crystalline product of insulin and an alkaline protein where the protein/insulin ratio is called the isophane ratio. This product gives a delayed and uniform insulin action with a reduction in the number of insulin doses necessary per day. Such a preparation may be made as follows 1.6 g of zinc-insulin crystals containing 0.4% of zinc are dissolved in 400 ml of water, with the aid of 25 ml of 0.1 N hydrochloric acid. To this are added aqueous solutions of 3 ml of tricresol, 7.6 g of sodium chloride, and sufficient sodium phosphate buffer that the final concentration is As molar and the pH is 6.9. 

Type 2 diabetes mellitus affects about 90% to 95% of individuals witii diabetes. Those with type 2 diabetes mellitus eitiier have a decreased production of insulin... 

The biopharmaceutical sector is largely based upon the application of techniques of molecular biology and genetic engineering for the manipulation and production of therapeutic macromolecules. The majority of approved biopharmaceuticals (described from Chapter 8 onwards) are proteins produced in engineered cell lines by recombinant means. Examples include the production of insulin in recombinant E. coli and recombinant S. cerevisiae, as well as the production of EPO in an engineered (Chinese hamster ovary) animal cell line. 

Human growth hormone (hGH) is a polypeptide with 191 amino acids. It is secreted by the pituitary gland. This hormone stimulates the production of insulin-like growth factor-1 (IGF-1) from the liver. Most of the positive effects of hGH are mediated by the IGF-1 system, which also includes specific binding proteins. 

Production of insulin is triggered when there is a rise in blood sugar, for example, after a meal. Most of our body cells have insulin receptors, which bind to the insulin secreted. When the insulin binds to the receptor, other receptors on the cell are activated to absorb sugar (glucose) from the bloodstream into the cell. 

Had this situation not changed, untold numbers of diabetics would have died or suffered serious health problems because of the shortage of animal insulin for their treatment. Fortunately, an important scientihc breakthrough made possible the production of insulin from another source recombinant DNA. Today, human insulin can he made synthetically by means of recombinant DNA, assuring that every diabetic in the country will have an adequate supply of the hormone they need to stay alive and remain healthy. 

Along with the production of insulin, many other medical uses have been achieved for recombinant DNA. This includes the production of erythropoetin, a hormone used to stimulate production of red blood cells in anemic people tissue plasminogen activator, an enzyme that dissolves blood clots in heart attack victims and antihemophilic human factor VIII, used to prevent and control bleeding for hemophiliacs. These three important genetically engineered proteins were all cloned in hamster cell cultures. 

Human insulin produced by recombinant DNA technology was first approved for general medical use in 1982, initially in the USA, West Germany, the UK and The Netherlands. As such, it was the first product of recombinant DNA technology to be approved for therapeutic use in humans. Production of insulin by recombinant means displays several advantages, including,... 

DEFECT OR DEFICIENCY i P Cells are destroyed, eliminating production of Insulin Insulin resistance combined with inability of p cells to produce appropriate quantities of insulin... 

SLOW p CELL DESTRUCTION Over a period of years P cells are destroyed, resulting in decreased production of insulin. 

Many chemicals important to genetic research have been produced at high levels, e.g. DNA ligase production in E. coli can be enhanced several hundred fold. Other enzymes can also be produced for industrial use and enhanced degradative ability has been generated for instance, enhanced petroleum degraders can be added to oil spills to accelerate clean-up operations. However, it is in the production of medically related compounds that this technology has been most successfully applied as, for example, in the production of insulin. 

Historically, insulin has been produced by extracting it from the pancreas of pigs and oxen, but the protein is not precisely the same as that found in humans and, although it functions in the same manner, its use can produce unwelcome side effects. Insulin produced from cloned DNA is identical to human insulin and is consequently considered safer. Another major advantage is that the production of insulin is not then limited by the number of pigs slaughtered. Using E. coli or yeasts, the process can be far more easily controlled and matched to demand so that this, and many other hormones, are now produced by this method. 

Switching from ordinary insulin to insulin lispro can reduce the production of insulin antibodies. 

Lu, D., Tamemoto, El., Shibata, El., Saito, I. and Takeuchi, T. (1998) Regulatable production of insulin from primary-cultured hepatocytes Insulin production is up-regulated by glucagon and cAMP and down-regulated by insulin. Gene Ther., 5, 888-895. 

Diabetes mellitus A disease marked by abnormal metabolism of glucose and other energy substrates caused by a defect in the production of insulin and/or a decrease in the peripheral response to insulin. 

Thiazolidinediones stimulate certain peroxisome proliferator-activatedreceptors (PPAR-y). PPAR-y is a nuclear receptor and, through a series of events, increases cellular production of insulin-dependent enzymes. This is an example of upregulation. The cell is then more sensitive to the decreased insulin levels found in a person with type 2 diabetes. The two thiazolidinediones currently on the market are rosiglitazone (Avandia, A.73) and... 

By the turn of the twentieth century, it was realized that diabetes was associated with the pancreas. In 1921, Banting and Best successfully isolated insulin from dog pancreas, and this was followed quickly by tests in humans. Eli Lilly began production of insulin in 1923. 

Figure 32-2. A schematic representation of the production of insulin and C-peptide from proinsulin in the pancreatic [3-cell. C-peptide acts as an indicator of endogenous insulin secretion, even in people who inject exogenous insulin.

Choi JH, Lee SJ, Lee SJ et al (2003) Enhanced production of insulin-like growth factor I fusion protein in Escherichia coli by coexpression of the down-regulated genes identified by transcriptome profiling. Appl Environ Microbiol 69 4737-4742... 

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