The influence of uridine and glutamine on cytidine transport and metabolism in rat brain primary cell culture.

The uptake of labelled cytidine from primary cell cultures from rat embryo brain has been examined in the presence of uridine and glutamine. When uridine and glutamine are incubated with cytidine at a ten-fold higher concentration cytidine uptake is stimulated noticeably but its conversion into cytidine nucleotides is inhibited. When equimolar concentrations of uridine and glutamine are used, both cytidine uptake and metabolism are noticeably increased. The results point to interesting interactions among nucleosides for their transport into living cells and their further utilization.