bilirubin

bilirubin (bil-i-ru´bin)

A red bile pigment found as sodium bilirubinate (soluble), or as an insoluble calcium salt in gallstones, formed from hemoglobin during normal and abnormal destruction of erythrocytes by the reticuloendothelial system; a bilin with substituents on the 2, 3, 7, 8, 12, 13, 17, and 18 carbon atoms and with oxygens on carbons 1 and 19. Excess b. is associated with jaundice. [bili- + L. ruber, red]
conjugated b. direct reacting b
delta b. the fraction of b. covalently bound to albumin; in conventional methods it is measured as part of conjugated b. Because of its covalent bond during the recovery phase of hepatocellular jaundice, it may persist in the blood for a week or more after urine clears.
direct reacting b. the fraction of serum b. which has been conjugated with glucuronic acid in the liver cell to form b. diglucuronide; so called because it reacts directly with the Ehrlich diazo reagent; increased levels are found in hepatobiliary diseases, especially of the obstructive variety.conjugated b;
indirect reacting b. the fraction of serum b. which has not been conjugated with glucuronic acid in the liver cell; so called because it reacts with the Ehrlich diazo reagent only when alcohol is added; increased levels are found in hepatic disease and hemolytic conditions.unconjugated b;
b. UDPglucuronyltransferase (gloo-ku´ron-il-trans´fer-as) an enzyme that catalyzes the reaction of UDPglucuronate and bilirubin forming UDP and bilirubin-glucuronoside; a deficiency of this enzyme is associated with Crigler-Najjar syndrome.
unconjugated b. indirect reacting b

 

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