The characteristics of nucleobase transport and metabolism by the perfused sheep choroid plexus

摘要: Abstract The uptake of nucleobases was investigated across the basolateral membrane sheep choroid plexus perfused in situ. maximal (Umax) for hypoxanthine and adenine, 35.51±1.50% 30.71±0.49% guanine, thymine uracil 12.00±0.53%, 13.07±0.48% 12.30±0.55%, respectively with a negligible backflux, except that (35.11±5.37% Umax). HPLC analysis revealed purine nucleobase pyrimidine can pass intact through enter cerebrospinal fluid CSF so lack backflux not result metabolic trapping cell. Competition studies hypoxanthine, adenine shared same transport system, while guanine were transported by separate mechanism nucleosides partially share transporter. collected vivo only two present hypoxanthine; an RCSF/Plasma 0.19±0.02 3.43±0.20, respectively. Xanthine urate, final products catabolism, could be detected even trace amounts. These results suggest activity xanthine oxidase brain is very low degradation purines carried out as far which then accumulates CSF. In conclusion, presence saturable systems at choroidal epithelium demonstrated, important distribution salvageable nucleobases, central nervous system.