title: Metabolism of the anti-hepatitis C virus nucleoside beta-D-N4-hydroxycytidine in different liver cells.
abstract: Beta-D-N4-hydroxycytidine (NHC) was found to have selective anti-hepatitis C virus (HCV) activity in the HCV replicon system (clone A). The intracellular metabolism of tritiated NHC was investigated in the HCV replicon system, Huh-7 cells, HepG2 cells, and primary human hepatocytes. Incubation of cells with 10 microM radiolabeled NHC demonstrated extensive and rapid phosphorylation in all liver cells. Besides the 5'-mono, -di-, and -triphosphate metabolites of NHC, other metabolites were characterized. These included cytidine and uridine mono-, di-, and triphosphates. UTP was the predominant early metabolite in Huh-7 cells and primary human hepatocytes, suggesting deamination of NHC as the primary catabolic pathway. The intracellular half-lives of radiolabeled NHC-triphosphate and of CTP and UTP derived from NHC incubation in Huh-7 cells were calculated to be 3.0 +/- 1.3, 10.4 +/- 3.3, and 13.2 +/- 3.5 h (means +/- standard deviations), respectively. Studies using monkey and human whole blood demonstrated more-rapid deamination and oxidation in monkey cells than in human cells, suggesting that NHC may not persist long enough in plasma to be delivered to liver cells.
authors.affiliation: Department of Pediatrics, Emory School of Medicine, and Veterans Affairs Medical Center, Decatur, Georgia 30033, USA.
authors.forename: Brenda I
authors.initials: BI
authors.lastname: Hernandez-Santiago
authors.forename: Thierry
authors.initials: T
authors.lastname: Beltran
authors.forename: Lieven
authors.initials: L
authors.lastname: Stuyver
authors.forename: Chung K
authors.initials: CK
authors.lastname: Chu
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Schinazi
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry; D000818:Animals; D000998:Antiviral Agents / Q000378:metabolism*; D001711:Biotransformation; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D003562:Cytidine / Q000031:analogs & derivatives* / Q000378:metabolism*; D006207:Half-Life; D000882:Haplorhini; D016174:Hepacivirus / Q000187:drug effects*; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D013058:Mass Spectrometry; D009705:Nucleosides / Q000378:metabolism
chemical_list: D000998:Antiviral Agents; D009705:Nucleosides; D003562:Cytidine; C010737:N(4)-hydroxycytidine; D000469:Alkaline Phosphatase