The transport of carcinoembryonic antigen from the circulation of the bile has been studied in the rat. Biliary excretion was directly proportional to the intravenously administered dose. Approximately 1-1.5% of the injected is excreted in the bile. Asialo-(carcinoembryonic antigen), asialo-fetuin and asialo-(alpha 1-acid glycoprotein) behaved similarly. The transit time through the liver for both native- and asialo-(carcinoembryonic antigen) was calculated as 47 min. Sialic acid content was not affected during biliary excretion. Glycoproteins that entered the liver cell lysosomes were not excreted in ther bile. A mechanism by which circulating proteins may by-pass the hepatocytes before being excreted in bile is suggested. Alternative mechanisms of protein entry into bile are discussed.
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Research Article| December 15 1980
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P Thomas; Studies on the mechanisms of biliary excretion of circulating glycoproteins. The carcinoembryonic antigen. Biochem J 15 December 1980; 192 (3): 837–843. doi: https://doi.org/10.1042/bj1920837
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