title: Plasma clearance of glycoproteins with terminal mannose and N-acetylglucosamine by liver non-parenchymal cells. Studies with beta-glucuronidase, N-acetyl-beta-D-glucosaminidase, ribonuclease B and agalacto-orosomucoid.
abstract: Glycoproteins having mannose and/or N-acetylglucosamine in the terminal non-reducing position [Stockert, Morell & Scheinberg (1976) Biochem. Biophys. Res. Commun. 68, 988--993], and various lysosomal enzymes [Stahl, Schlesinger, Rodman & Doebber (1976) Nature (London) 264, 86--8] are rapidly cleared from plasma by the liver after intravenous administration. A liver cell-separation technique was used to determine the cellular localization of 125I-labelled beta-glucuronidase, ribonuclease B, agalacto-orosomucoid and asialo-orosomucoid. On a specific readioactivity basis, all ligands except 125I-labelled asialo-orosomucoid were enriched in the non-parenchymal cell fraction. Isolated cells, fixed and stained for beta-glucuronidase or N-acetyl-beta-D-glucosaminidase activity after intravenous injection of the enzymes, showed enrichment in the non-parenchymal cell fraction (probably Kupffer cells). After uptake by the non-parenchymal cells, liver lysosomal beta-glucuronidase and N-acetyl-beta-D-glucosaminidase showed degradation half-times of 2.2 and 0.4 days respectively.
mesh_terms: D000117:Acetylglucosamine; D000118:Acetylglucosaminidase / Q000378:metabolism; D000818:Animals; D005260:Female; D005966:Glucuronidase / Q000378:metabolism; D006023:Glycoproteins / Q000097:blood*; D008024:Ligands; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008247:Lysosomes / Q000201:enzymology; D008358:Mannose; D009961:Orosomucoid / Q000031:analogs & derivatives / Q000378:metabolism; D051381:Rats; D012260:Ribonucleases / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D008024:Ligands; D009961:Orosomucoid; C018203:agalacto-orosomucoid; D012260:Ribonucleases; D005966:Glucuronidase; D000118:Acetylglucosaminidase; D008358:Mannose; D000117:Acetylglucosamine