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Diabetes Mellitus

Diabetes mellitus is a metabolic disorder characterised by hyperglycemia due to defects in the production or action of the insulin.
Diabetes mellitus occurs when the patient's Insulin is either absent, not present in high enough quantities for the boy's needs, or not used correctly by the body. [1] Insulin is a hormone that is produced by specialised cells (Beta cells) of the Pancreas. In addition to helping glucose enter the cells, insulin is also important in tightly regulating the level of glucose in the blood. After a meal, an individual's blood glucose level rises. In response to this increase, the Pancreas normally releases more insulin into the bloodstream to to help glucose enter the cells of the body and lower blood glucose levels after a meal. When the blood glucose levels are lowered, less insulin is released from the Pancreas. In healthy individuals, this regulatory system helps to keep blood glucose levels in a tightly controlled range. However, in patients with diabetes, insulin secretion is abnormal, resulting in high levels of blood glucose (hyperglycemia) which must be treated.

According to the American Diabetes Association [2] the different cases of diabetes mellitus can be classified as:

Type 1 Diabetes [3]

It is also known as insulin-dependent diabetes mellitus. It can be due to an auto-immune response against the pancreatic beta cells preventing the production of insulin. Many cases of Type 1 diabetes have non-identified etiology so they are considered to be idiopathic.

Type 2 Diabetes [4]

It is also known as non-insulin dependent diabetes mellitus and is caused due to insulin no longer triggering its signalling cascade. Increasing obestiy in the world is making this type of diabetes increasingly common.

Type 2 Diabetes is prevalent in certain indigenous populations including the Pima Indians in the USA and Aborigines in Australia. This is thought to be due to several environmental factors such as the western diet and obesity but a "faulty gene" is also though to be contributory though has not yet been identified.

Other Specific Types of Diabetes [5]

Gestational diabetes mellitus (GDM) [6]

It normally occurs during the 3rd trimester of pregnancy.
50 % of women who get GDM usually get Type 2 diabetes later on in life.

Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) [7]

In pateints with IGT there is a loss in insulin sensitivity leading to hyperinsulinism[8]. It is an intermediate state where the glycemia is not high enough to be considered diabetes but being higher than the normal levels.

Diabetes Insipidus

Nephrogenic diabetes insipidus is caused by mutations in aquaporin 2. Usually AQP2 is trafficked to the cell membrane where it facilitates the reabsorption of water into the cell. In the diseased state the channels are retained inside the cell resulting in the inability to control the concentration of urine being produced [9].


  1. http://www.medicinenet.com/diabetes_mellitus/page2.htm
  2. American Diabetes Association. Diagnosis and Classification of Diabetes Mellitus. Diabetes Care January 2009 vol. 32 no. Supplement 1 S62-S67fckLRdoi: 10.2337/dc09-S062
  3. Surg Annu. 1978;10:1-21. Replacement of pancreatic beta cells as treatment for diabetes mellitus: a review. Jonasson O, Hoversten GH.
  4. Acta Med Indones. 2010 Oct;42(4):204-8. Insulin resistance profile among siblings of type 2 diabetes mellitus (preliminary study). Purnamasari D, Soegondo S, Oemardi M, Gumiwang I. Department of Internal Medicine, Faculty of Medicine, University of Indonesia - dr. Cipto Mangunkusumo Hospital. Jl. Diponegoro no. 71, Jakarta Pusat 10430, Indonesia.
  5. American Diabetes Association. Diagnosis and Classification of Diabetes Mellitus. Diabetes Care January 2009 vol. 32 no. Supplement 1 S62-S67fckLRdoi: 10.2337/dc09-S062
  6. Diabetes Care. 2010 Oct 26. [Epub ahead of print] Body and Liver Fat Mass Rather Than Muscle Mitochondrial Function Determines Glucose Metabolism in Women with a History of Gestational Diabetes. Prikoszovich T, Winzer C, Schmid AI, Szendroedi J, Chmelik M, Pacini G, Krssák M, Moser E, Funahashi T, Waldhäusl W, Kautzky-Willer A, Roden M. Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria.
  7. Clin Chem. 2010 Nov 9. [Epub ahead of print] Prediabetes as a Therapeutic Target. Pour OR, Dagogo-Jack S. Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Tennessee Health Science Center, Memphis, TN.
  8. Reaven G. M., Greenfield M. S., Diabetes, 30, (Suppl. 2), 66—75 (1981).
  9. The Journal of Cell Biology. (2003). Reversed polarized delivery of an aquaporin-2 mutant causes dominant nephrogenic diabetes insipidus 163(5):1099-109
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