To our surprise, insulin was the first hormone identified (late 1920's) which won the doctor and medical student who discovered it the Nobel Prize (Banting and Best). They discovered insulin by tying a string around the pancreatic duct of several dogs. When they examined the pancreas of these dogs several weeks later, all of the pancreas digestive cells were gone (died and were absorbed by the immune system) and the only thing left was thousands of pancreatic islets. They then isolated the protein from these islets and behold, they discovered insulin. Note that there are other hormones produced by different types of cells within pancreatic islets (glucagon, somatostatin, etc) but insulin is produced in far greater amounts under normal conditions making the simple approach used by Banting and Best quite successful.
Insulin is a hormone. And like many hormones, insulin is a protein. Insulin is secreted by groups of cells within the pancreas called islet cells. The pancreas is an organ that sits behind the stomach and has many functions in addition to insulin production. The pancreas also produces digestive enzymes and other hormones. Carbohydrates (or sugars) are absorbed from the intestines into the bloodstream after a meal. Insulin is then secreted by the pancreas in response to this detected increase in blood sugar. Most cells of the body have insulin receptors which bind the insulin which is in the circulation. When a cell has insulin attached to its surface, the cell activates other receptors designed to absorb glucose (sugar) from the blood stream into the inside of the cell.
Without insulin, you can eat lots of food and actually be in a state of starvation since many of our cells cannot access the calories contained in the glucose very well without the action of insulin. This is why Type 1 diabetics who do not make insulin can become very ill without insulin shots. Insulin is a necessary hormone. Those who develop a deficiency of insulin must have it replaced via shots or pumps (Type 1 Diabetes). More commonly, people will develop insulin resistance (Type 2 Diabetes) rather than a true deficiency of insulin. In this case, the levels of insulin in the blood are similar or even a little higher than in normal, non-diabetic individuals. However, many cells of Type 2 diabetics respond sluggishly to the insulin they make and therefore their cells cannot absorb the sugar molecules well. This leads to blood sugar levels which run higher than normal. Occasionally Type 2 diabetics will need insulin shots but most of the time other methods of treatment will work.
Therefore, the chief feature of diabetes is the lack of insulin. Diabetes is a circumstance in which a break down occurs in the metabolism of the food into power for the human body. It is a serious disorder that effects millions and millions of people each year. Diabetes is one of the oldest diseases known to this date. Since the Ancient days, scientist have made many medical discovers that helps treat diabetes.(Dolger and Seeman 14). Accordingly, diabetes is a chronic, genetically determined, debilitating disease that affects every organ system. There are two major types of diabetes: Type I and Type II. Type I or insulin dependent diabetes mellitus (IDDM), is caused by the autoimmune destruction of the insulin producing cells of the pancreas and is usually, but not always diagnosed in childhood. People...