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The mechanism of biliary excretion of α 1 ‐acid glycoprotein in the rat: Evidence for a molecular weight‐dependent, nonreceptor‐mediated pathway
Author(s) -
Thomas Peter,
Toth Carol A.,
Zamcheck Norman
Publication year - 1982
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840020610
Subject(s) - mechanism (biology) , glycoprotein , chemistry , bile acid , excretion , medicine , endocrinology , biochemistry , biology , philosophy , epistemology
The transport of human α 1 ‐acid glycoprotein from the circulation to the bile has been studied in the rat. Biliary excretion was proportional to the i.v. injected dose, and the percentage excreted remained constant. The amount excreted in the bile (over 4 hr) was inversely related to the rate of hepatic (hepatocyte) uptake and the galactose receptor which is specific for asialo glycoproteins was not involved. Reinjection of the glycoprotein excreted in bile resulted in a similar proportion of the dose being reexcreted, suggesting that a subset of the glycoprotein is not selected for excretion in bile. Transit times from blood to bile for glucagon, insulin, α 1 ‐acid glycoprotein, fetuin, albumin, and carcinoembryonic antigen were directly related to their molecular weights. Removal of sialic acid from the asialo glycoproteins did not affect these transit times. Possible mechanisms for the biliary excretion of α 1 ‐acid glycoprotein are discussed.