Deoxyribocytidine Is Salvaged Not Only into DNA but Also into Phospholipid Precursors.: IV. Exogenous Deoxyribocytidine Can Be Used with the Same Efficacy as (Ribo)cytidine for Lipid Activation

Abstract

Utilisation of exogenous (ribo)cytidine (3H-CR) and deoxyribocytidine (3H-CdR) for DNA/RNA synthesis and for activation of phospholipid intermediates was compared in human tonsillar lymphocytes. Incorporation of 3H-CdR into dCDP-choline and into dCDP-DAG was similar or even higher than labelling of CDP-choline and CDP-DAG from 3H-CR. No interconversion was found between CDP-DAG and dCDP-DAG, as shown by TLC separation of the ribo- and deoxyribocytidine derivatives. Moreover, a strict separation was found between the salvage pathways of deoxyribocytidine and (ribo)cytidine, as 4000-fold excess of non labelled (ribo)cytidine did not show any specific effect on 3H-dCDP-DAG labelling from exogenous 3HCdR.