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, 20:00, 23 July 2010
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{| cellpadding="10" cellspacing="0" border="1"
| Also known as:
|'''Blood Urea Nitrogen - BUN'''
|-
| See also:
|'''[[Blood urea nitrgoen|Urea in lizards]]'''
|}
==Description==
Urea is a form of nitrogenous waste formed from [[Ammonia|ammonia]] via the urea cycle in the liver. It freely crosses lipid membranes and is filtered into the glomerular filtrate in the renal glomerulus. A proportion of this filtered urea is reabsorbed passively before final excretion and it forms a vital of the concentration gradient needed to prevent passive diuresis.
==Clinical Significance==
An increase in serum concentrations of urea and creatinine is known as '''[[Azotaemia|azotaemia]]''' and it is found almost exclusively in animals with kidney disease.
Blood urea coentration may be elevated independently of creatinine for the following reasons:
*Gastro-intestinal haemorrhage, as with [[Gastric Ulcer - Dog|gastro-duodenal ulceration]].
*Diet with high purine content, such as liver.
Reduced urea concentration:
[[Category:Blood_Sample]][[Category:Dog]][[Category:Cat]][[Category:Cattle]][[Category:Sheep]][[Category:Horse]][[Category:Pig]][[Category:Donkey]][[Category:To_Do_-_James]]