Urea is the end product of protein metabolism. Synthesis of urea occurs in the liver from ammonia nitrogen and amino acids as a result of consecutive reactions (the urea cycle).
Urea is primarily excreted by the kidneys: excreted by the glomeruli and reabsorbed (about 35%) in the proximal tubule passively due to the reabsorption of water. With the final urine from the body takes about 75% of the urea formed in the liver.
Normal content of urea in the blood (the level of urea in normal) ranges from 2.5-8.3 mmol/L in the mixed diet. Maximum urea clearance is 75 ml/min and depends on the diuresis.
The synthesis of urea in the body quite stable. Violation is observed with very severe liver disease or hereditary (congenital) pathology of liver enzymes. Especially the high content of urea (50 mmol/l and above) is found in acute renal failure. This greatly decreases the excretion of urea with urine.
Indicanuria is to identify indican (potassium salt of indoxyl sulfuric acid) in the urine. Indicanuria observed in diseases occurring with increased protein breakdown or intensive rotting protein in the intestine.