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uro·bi·lin·o·gen .yu̇r-ə-bī-'lin-ə-jən, -.jen n any of several chromogens that are reduction products of bilirubin and yield urobilins on oxidation called also stercobilinogen
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n.
a colourless product of the reduction of the bile pigment bilirubin. Urobilinogen is formed from bilirubin in the intestine by bacterial action. Part of it is reabsorbed and returned to the liver; part of it is excreted in the faeces (a trace may also appear in the urine). When exposed to air, urobilinogen is oxidized to a brown pigment, urobilin.
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uro·bi·lino·gen (u″ro-bĭ-linґo-jən) [urobilin + -gen] a colorless compound formed in the intestines by the reduction of bilirubin. Some is excreted in the feces, where by oxidation it becomes urobilin, and some is reabsorbed and re-excreted either in the bile as bilirubin or in the urine, where it is later oxidized to urobilin.Medical dictionary. 2011.