title: Evaluation of cellular purine transport and metabolism in the Caco-2 cell using comprehensive high-performance liquid chromatography method for analysis of purines.
abstract: Using Caco-2 cells and our previously developed high-performance liquid chromatography method for quantification of purine bases, nucleosides, and nucleotides, we evaluated cellular purine transport and uptake. The analytes were separated using YMC-Triart C18 column with gradient elution. We used Caco-2 cells as intestinal model cells and monitored purine transport across a monolayer for 2 h. The degree of change of purine concentrations in the permeate was very slight; however, it was possible to simultaneously determine these parameters for all purines because of our method's high sensitivity. In the present study, the purine bases (adenine, guanine, hypoxanthine, and xanthine) showed a relatively high permeability as compared with the nucleosides (adenosine, guanosine, inosine, and xanthosine). Increased concentration of metabolites in the permeate was also observed following the addition of purines. In a cell uptake assay, both the cell culture medium (extracellular) and the cells extracted from Caco-2 with acetonitrile:water (7:3) (intracellular) were measured. The additional nucleoside did not increase significantly within the cells. On the other hand, we observed that nucleotide, such as ATP, increased in the cell in a time-dependent manner following the addition of nucleoside. The additional nucleosides were considered to be rather recycled via the salvage pathway than metabolized to purine bases and/or uric acid in the cell. Such differences might have affected the increase in the serum uric acid levels depending on purine form.
authors.affiliation: a Laboratory of Biomedical and Analytical Sciences, Faculty of Pharma-Science, Teikyo University , Itabashi, Tokyo , Japan.
authors.forename: T
authors.initials: T
authors.lastname: Fukuuchi
authors.affiliation: a Laboratory of Biomedical and Analytical Sciences, Faculty of Pharma-Science, Teikyo University , Itabashi, Tokyo , Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: a Laboratory of Biomedical and Analytical Sciences, Faculty of Pharma-Science, Teikyo University , Itabashi, Tokyo , Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yamaoka
authors.affiliation: a Laboratory of Biomedical and Analytical Sciences, Faculty of Pharma-Science, Teikyo University , Itabashi, Tokyo , Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kaneko
mesh_terms: D000241:Adenosine / Q000302:isolation & purification / Q000378:metabolism*; D001692:Biological Transport; D018938:Caco-2 Cells; D002851:Chromatography, High Pressure Liquid; D006151:Guanosine / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans
chemical_list: D006151:Guanosine; D000241:Adenosine
keywords: Caco-2 cells; HPLC; metabolism; simultaneously determination; transport