title: Substrate/Product-targeted NMR monitoring of pyrimidine catabolism and its inhibition by a clinical drug.
abstract: We report the application of one-dimensional triple-resonance NMR to metabolic analysis and thereon-based evaluation of drug activity. Doubly (13)C/(15)N-labeled uracil ([(15)N1,(13)C6]-uracil) was prepared. Its catabolic (degradative) conversion to [(13)C3,(15)N4]-β-alanine and inhibition thereof by gimeracil, a clinical co-drug used with the antitumor agent 5-fluorouracil, in mouse liver lysates were monitored specifically using one-dimensional triple-resonance ((1)H-{(13)C-(15)N}) NMR, but not double-resonance ((1)H-{(13)C}) NMR, in a ratiometric manner. The administration of labeled uracil to a mouse resulted in its non-selective distribution in various organs, with efficient catabolism to labeled β-alanine exclusively in the liver. The co-administration of gimeracil inhibited the catabolic conversion of uracil in the liver. In marked contrast to in vitro results, however, gimeracil had practically no effect on the level of uracil in the liver. The potentiality of triple-resonance NMR in the analysis of in vivo pharmaceutical activity of drugs targeting particular metabolic reactions is discussed.
authors.affiliation: Advanced Biomedical Engineering Research Unit, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Hisatsugu
authors.initials: H
authors.lastname: Yamada
authors.forename: Keigo
authors.initials: K
authors.lastname: Mizusawa
authors.forename: Ryuji
authors.initials: R
authors.lastname: Igarashi
authors.forename: Hidehito
authors.initials: H
authors.lastname: Tochio
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shirakawa
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tabata
authors.forename: Yu
authors.initials: Y
authors.lastname: Kimura
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Kondo
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Aoyama
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Sando
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008807:Mice, Inbred BALB C; D015394:Molecular Structure; D011725:Pyridines / Q000494:pharmacology*; D014498:Uracil / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism
chemical_list: D011725:Pyridines; D014498:Uracil; C104201:gimeracil