A uroporphyrin; an acyclic tetrapyrrole that is one of the natural breakdown products of heme via choleglobin, verdohemochrome, biliverdin, bilirubin, and d-urobilinogen; a urinary pigment that gives a varying orange-red coloration to urine according to its degree of oxidation. SYN: urohematin, urohematoporphyrin.
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uro·bi·lin .yu̇r-ə-'bī-lən n any of several brown bile pigments formed from urobilinogens and found in normal feces, in normal urine in small amounts, and in pathological urines in larger amounts
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uro·bi·lin (u″ro-biґlin) [uro- + bilin] a brown pigment, an oxidized form of urobilinogen, found in the feces and sometimes in urine left standing in the air.Medical dictionary. 2011.