title: Hepatic uptake of [99mTc]galactosyl-neoglycoalbumin is sensitive to receptor quantity.
abstract: [Technetium-99m]galactosyl-neoglycoalbumin (TcNGA) is a synthetic radioligand specific to the receptor, hepatic binding protein (HBP), which resides exclusively at the cell surface of hepatocytes. If the TcNGA time-activity data are to provide valid estimates of receptor biochemistry via pharmacokinetic modeling, the shape of the hepatic uptake curve must change with alterations in receptor concentration or affinity. An index of TcNGA hepatic uptake, T90, was obtained by calculating the time at which the liver time-activity curve reached 90% of its maximum. Receptor quantity was measured by Scatchard binding assay of liver biopsy samples obtained prior to each TcNGA study. The range of T90 was 3.7-16.8 min; HBP quantity ranged from 0.022 to 0.100 mumol. Significant correlation (r) and slope (b) was observed between T90 and HBP quantity (r = 0.82, P = 0.003; tb = 3.98, P = 0.003). We concluded that the hepatic uptake of TcNGA is sensitive to HBP quantity.
authors.affiliation: Division of Nuclear Medicine, University of California, Davis, Medical Center, Sacramento 95817.
authors.forename: M
authors.initials: M
authors.lastname: Kudo
authors.forename: D R
authors.initials: DR
authors.lastname: Vera
authors.forename: W L
authors.initials: WL
authors.lastname: Trudeau
authors.forename: R C
authors.initials: RC
authors.lastname: Stadalnik
mesh_terms: D000328:Adult; D000368:Aged; D000418:Albumins / Q000378:metabolism / Q000493:pharmacokinetics*; D037263:Asialoglycoprotein Receptor; D002352:Carrier Proteins / Q000032:analysis*; D005260:Female; D005690:Galactose / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008107:Liver Diseases / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000378:metabolism / Q000493:pharmacokinetics*; D011877:Radionuclide Imaging; D012709:Serum Albumin / Q000378:metabolism*
chemical_list: D000418:Albumins; D037263:Asialoglycoprotein Receptor; D002352:Carrier Proteins; D015609:Organotechnetium Compounds; D012709:Serum Albumin; C027122:hepatic sialoglycoprotein receptor; C036586:technetium Tc 99m neogalactoalbumin; D005690:Galactose