urobilinogogeeniä

Urobilinogeenia, also known as urobilinogen, is a colorless tetrapyrrole compound produced in the digestive tract of vertebrates. It is a metabolic byproduct of bilirubin, a pigment formed from the breakdown of heme in red blood cells. Bilirubin is conjugated in the liver to form bilirubin glucuronide, which is then secreted into the bile. In the intestines, bacteria deconjugate the bilirubin glucuronide, and then reduce it to urobilinogen.

A portion of the urobilinogen produced in the intestines is reabsorbed into the portal circulation and transported back to the liver. This process is called the enterohepatic circulation. From the liver, some urobilinogen is excreted in the bile, while a small amount is filtered by the kidneys and excreted in the urine. The remaining urobilinogen in the intestines is further metabolized by bacteria into stercobilinogen and then oxidized to stercobilin, which gives feces its characteristic brown color.

In urine, urobilinogen is typically oxidized to urobilin, a yellow-orange pigment that contributes to the normal color of urine. The concentration of urobilinogen in urine can vary. Small amounts are normally present, but elevated levels can indicate various conditions. For instance, increased urinary urobilinogen can be a sign of hemolytic anemia, where red blood cells are destroyed at an accelerated rate, leading to increased bilirubin production and subsequent urobilinogen formation. Liver diseases, such as hepatitis or cirrhosis, can also cause elevated urinary urobilinogen because the damaged liver is less efficient at reabsorbing and processing it from the portal circulation. Conversely, a complete absence of urobilinogen in urine, although rare, might suggest bile duct obstruction. Medical professionals use urobilinogen tests as part of routine urinalysis to help diagnose and monitor liver and blood disorders.