by Tarek Musslimani

Created on: June 17, 2009   Last Updated: January 20, 2010

Diabetes mellitus is an endocrine disorder in which the beta-islet cells of the pancreas secrete deficient amounts of the hormone insulin. Insulin is a polypeptide hormone that is required for the transport of glucose to the inner side of the cells in the body. There, it is metabolized by the glycolysis process in order to generate energy rich molecules in the form of ATP or adenosine-triphosphate. Glucose is the main type of molecules that are used in order to generate energy for the cells. This is the case especially for the cells of the nervous system. Especially glucose dependent is the function of the brain. In addition insulin functions by stimulating the synthesis of glycogen which is a polymer of glucose. Glycogen is degraded into glucose by another hormone that is called glucagon. It is an antagonist to insulin in its function. It stimulates the release of glucose which needed by the tissues. Glycogen functions in a stress situation like two other hormones. These are growth hormone and cortisol which stimulate the release of glucose from the tissues. As a result these three hormones are antagonists in function to insulin.

Insulin deficiency is not only important for glucose transport but is also important for the transport of potassium across the cellular membrane to the inner side of the cells. Insulin deficiency leads to hyperkalemia condition which can in turn affect the heart function. As a result of insulin deficiency there is increased amounts of glucose in the blood. A condition that is called hyperglycemia.

As the body's use of glucose in impaired, the body starts to seek alternative sources of energy. Therefore degradation of lipids into fatty acids begin to predominate. Fatty acids are the ultimate source of energy in the case of untreated diabetes mellitus. Fatty acids are metabloized to ketone bodies such as aceto-acetate which is a keto-acid. ketones are the ultimate source of energy for neurons in diabetic patients. One symptom of diabetes mellitus is urine that smells like acetone due to the existence of ketones in the urine. Another symptom is weight loss due to the decreased utilization of glucose.

Diabetes mellitus is divided into primary and secondary diabetes mellitus. Primary diabetes mellitus is in turn divided into two types. These are type I or insulin dependent diabetes mellitus and Type II or non insulin dependent diabetes mellitus. Secondary diabetes mellitus arises due to causes other than insulin deficiency such as in cushing

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