urea nitrogen

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Related to urea nitrogen: uric acid, Urine urea nitrogen


1. the diamide of carbonic acid found in urine, blood, and lymph, the chief nitrogenous constituent of urine, and the chief nitrogenous end-product of protein metabolism; it is formed in the liver from amino acids and from ammonia compounds.
2. a pharmaceutical preparation of this compound, administered intravenously as an osmotic diuretic to lower intracranial or intraocular pressure, injected transabdominally into the amniotic sac to induce abortion of a second trimester pregnancy, and included in topical preparations to moisten and soften rough, dry skin.

The amount of urea in the urine increases with the quantity of protein in the diet because urea is an endogenous and exogenous waste product: endogenous because some of it is derived from breakdown of body protein as tissues undergo disintegration and repair, and exogenous because some of it is derived from the deamination of amino acids absorbed from the intestinal tract but not utilized by the body. In severe nephritis or other disorders leading to renal failure, the concentration of urea in the blood may be greatly increased, as revealed by measurement of the blood urea nitrogen (BUN).
urea concentration test a test of renal efficiency, based on the fact that urea is absorbed rapidly from the stomach into the blood and is excreted unaltered by the kidneys; 15g of urea is given with 100mL of fluid, and the urine collected after 2 hours is tested for urea concentration.
urea nitrogen the urea concentration of serum or plasma, conventionally specified in terms of nitrogen content and called blood urea nitrogen (BUN), an important indicator of renal function.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

u·re·a ni·tro·gen

the portion of nitrogen in a biologic sample, such as blood or urine, that derives from its content of urea.
See also: blood urea nitrogen.
Farlex Partner Medical Dictionary © Farlex 2012

urea nitrogen

See BUN.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
While a strong positive association was seen for blood urea nitrogen as a marker for kidney function both at baseline (r= 0.728; p=0.000) and follow up (r=0.747; p=0.001).
Blood metabolites: Blood samples of two animals of each group were analyzed for blood urea nitrogen and blood glucose to see the nitrogen available in blood stream be used for recycling and energy available for microbial protein and volatile fatty acid synthesis in the body.
Total protein, urea nitrogen and glucose levels in serum were measured using commercial assay kits (Nanjing Jiancheng Bioengineering Institute, Nanjing, China) by following the manufacturer's protocols.
Patients admitted on off-hours had lower serum albumin (P<0.001) and higher white blood cell (P<0.001), blood urea nitrogen (P<0.001), potassium (p<0.001), prothrombin time (P=0.034), INR (P=0.040), Child-Pugh score (P=0.006), and ALBI score (P<0.001) than those admitted on regular hours (Table 1).
The levels of urinary albumin excretion, blood creatinine, and urea nitrogen were detected to evaluate the diabetic renal dysfunction.
The estimation of endogenous urea nitrogen (EUN) of 0.265 g N[kg.sup.-1] of metabolic weight was obtained by urinary total nitrogen excretion (Y) and nitrogen intake (X) ([??] = -0.2652 + 0.4743X, [r.sup.2] = 0.43).
The reasons for increasing urea nitrogen are eating foods with high nitrogen content,
There was no change in creatinine, blood urea nitrogen (BUN), potassium, calcium, magnesium, uric acid, parathyroid hormone, or hemoglobin levels.
The blood creatinine, lactic acid, seeum calcium, serum urea and serum urea nitrogen were estimated using standard laboratory methods.
Enzymatically measured creatinine concentration (Roche Diagnostics, COBAS 8000) was significantly decreased 24 h after admission (Table 1), inconsistent with clinical features and blood urea nitrogen concentration.
The blood urea nitrogen (BUN) and creatinine were higher (P<0.05) in lambs fed RUP25 and RUP35 diets than those fed RUP45 and RUP55 diets.