UNDERSTANDING DIABETES

Diabetes mellitus, or diabetes, is an illness in which there is an abnormally high level of glucose in the blood. Depending on how high glucose level is and how long it has been high, one may feel fairly well, or one may be so sick that require hospitalization. Usually, doctor will test for diabetes if one has symptoms such as thirst, frequent urination, weight loss, blurred vision, and fatigue.

Glucose and its Uses in the body

Glucose is asugar and is one of the energy sources of the body. Some organs in our bodies, such as the brain, are particularly dependent upon glucose as an energy source, so it is very important that the body maintain the amount of glucose in the blood in the normal range: if the level is too high or too low, there are serious con­sequences. To avoid these consequences, the body has a complex set of mechanisms to keep the glucose in the normal range.

The liver is in charge of taking up and releasing glucose into the bloodstream. After a meal, the blood carrying nutrients from digestion first flows through the liver, which removes the excess glucose. When the glucose level in the blood drops (for example, after fasting or exercising), the liver does the opposite and releases glucose into the bloodstream. The liver knows how to regulate the level of glucose in the blood because it receives signals from hormones, which are chemical mes­sengers in the blood. The two hormones that are particularly important in diabetes are insulin and glucagon.

These hormones are produced in the islets of Langerhans of the pancreas, an elongated organ located behind and below the stomach in the abdomen. There are about a million islets in a normal pancreas, and they consist of several types of cells— the beta cells make insulin and the alpha cells make glucagons. 

In a person with diabetes, the beta cells in the islets fail, and this alters the bal­ance of insulin and glucagon actions on the tissues. The cause and degree of beta cell failure varies in different kinds of diabetes,

Insulin

Insulin is the hormone that ensures that the glucose entering the bloodstream from the digestion of food is removed from the blood. It does this by switching the body’s metabolism so that it uses glucose instead of fat for its energy needs. Insu­lin also signals the body to make glycogen (a storage form of glucose) and to use glucose to make triglycerides (another important energy source) for storage in fat cells. Insulin does all this by its effects on liver cells, muscle cells, and fat cells

• In the liver, insulin makes the liver cells convert glucose into glycogen, a storage form of glucose, and make triglycerides, a storage form of fat.   
• In the muscles, insulin allows the glucose transport into the muscle cells.   
• In the fat tissues, insulin stops the breakdown of triglycerides and release of fatty acids into the bloodstream.   

Glucagon

Glucagon acts in an opposite manner to insulin: it switches the body’s metabolism so that it uses fatty acids instead of glucose as its energy source, and it signals the body to increase glucose production. Glucagon achieves this by instructing the liver cells to break down glycogen and release glucose into the bloodstream. It also sig­nals the fat tissues to break down triglycerides and release glycerol and fatty acids into the blood.

Thus, it is the balance of insulin and glucagon that regulates the glucose levels in the blood during the fed and fasting states.