title: Salvage of circulating pyrimidine nucleosides by tissues of the mouse.
abstract: The metabolism of pyrimidine nucleosides present in the plasma of the mouse has been examined. Uridine and cytidine are rapidly cleared from the circulation with t1/2 of less than 5 min. Uracil, deoxycytidine, deoxyuridine, and thymidine are cleared more slowly with t1/2 of 9 to 13 min. Various tissues differed markedly in the extent of nucleotide formation from circulating nucleosides. Cytidine and uridine are predominantly converted to nucleotides (greater than 50%) rather than catabolized, whereas uracil is almost entirely degraded. Thymidine, deoxyuridine, and deoxycytidine are intermediate in the extent of their conversion to nucleotides: 8.9 to 21% of these nucleosides are salvaged in the mouse. Both anabolic and catabolic routes are important in the metabolism of pyrimidine nucleosides in vivo.
mesh_terms: D000818:Animals; D003562:Cytidine / Q000378:metabolism; D003841:Deoxycytidine / Q000378:metabolism; D003857:Deoxyuridine / Q000378:metabolism; D006207:Half-Life; D008297:Male; D008657:Metabolic Clearance Rate; D051379:Mice; D011741:Pyrimidine Nucleosides / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism; D014018:Tissue Distribution; D014498:Uracil / Q000378:metabolism; D014529:Uridine / Q000378:metabolism
chemical_list: D011741:Pyrimidine Nucleosides; D003841:Deoxycytidine; D014498:Uracil; D003562:Cytidine; D013936:Thymidine; D003857:Deoxyuridine; D014529:Uridine