A metabolic disorder characterized by excessive urine excretion and persistent thirst; often caused by a dysfunction in hormonal regulation (e.g. dysfunctional insulin regulation in diabetes mellitus and dysfunctional vasopressin regulation in diabetes insipidus)
Diabetes is a metabolic disorder characterized by excessive urine excretion (polyuria) and persistent thirst.
In diabetes mellitus, the condition is characterized by an irregular blood sugar concentration. Insulin is supposed to incite the cells to take up glucose from the bloodstream. Liver cells, for instance, are stimulated by the insulin to absorb glucose molecules and convert the excess into glycogen. Without the regulatory function of insulin, the result is an excess of sugar in the bloodstream and urine.
Diabetes caused by insulin problems may be classified as type 1 (juvenile-onset) or type 2 (adult-onset). In type 1, the underlying cause is typically genetic. It is usually diagnosed in children and young adults. Nevertheless, it can appear at any age. (Ref. 1) In type 2, the condition is often associated with a poor diet (e.g. high carbohydrate intake) and an unhealthy lifestyle. This form of diabetes commonly develops later in life, often in middle age. However, it can still develop at any age. (Ref. 1)
In type 1 diabetes, the body fails to produce enough insulin because the immune system tends to attack and destroy pancreatic cells that produce and release insulin. (Ref. 1) In type 2 diabetes, the condition is caused by the combination of insufficient insulin production and the resistance to insulin. (Ref. 2) The body does not produce enough insulin molecules and when present the body fails to use them well. The cells eventually develop resistance to insulin action and as such the insulin molecules cannot render their effect on the target cells.
This form of diabetes develops in women during their pregnancy and often goes away after childbirth. However, the predisposition to developing type 2 diabetes later in life is increased. (Ref. 1,3)
This form of diabetes is less common than diabetes mellitus. They are not related to each other. Diabetes insipidus is not caused by dysfunctional insulin regulation instead another hormone is involved — the vasopressin (also called antidiuretic hormone, ADH). This hormone is responsible for regulating water retention in the kidneys.
Diabetes insipidus is characterized by excessive production of dilute urine. This is caused by the kidney tubules not reabsorbing water. (Ref. 4) Possible underlying causes are as follows:
• Renal tubules have defective receptors for ADH, as what occurs in nephrogenic diabetes insipidus where gene mutations, chronic kidney disease, and certain medications cause the kidneys to not respond to ADH as they normally should. (Ref. 4)
• Defective aquaporin water channel in the collecting duct
• Pituitary gland does not release an adequate amount of ADH, as in the case of central diabetes insipidus where the pituitary gland is damaged, e.g. from surgery, infection, tumor, or physical injury. (Ref. 4)
- National Institute of Diabetes and Digestive and Kidney Diseases. (2020, May 18). What is Diabetes? | NIDDK. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes
- Diabetes | Healthy People 2020. (2020). Healthypeople.Gov. https://www.healthypeople.gov/2020/topics-objectives/topic/diabetes
- Diabetes. (2020). Medlineplus.Gov; National Library of Medicine. https://medlineplus.gov/diabetes.html
- National Institute of Diabetes and Digestive and Kidney Diseases. (2020, May 18). Diabetes Insipidus | NIDDK. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/kidney-disease/diabetes-insipidus
- Saliva Could Become Standard for Diabetes Monitoring – BioTechniques. (2020, April 21). BioTechniques. https://www.biotechniques.com/diagnostics/news_novel-method-could-lead-to-non-invasive-diabetes-monitoring/ (New non-invasive method of monitoring diabetes)
©BiologyOnline. Content provided and moderated by BiologyOnline Editors.