The salvage of deoxycytidine into dCDP-diacylglycerol by macrophages and lymphocytes.

Extracellular deoxycytidine (CdR) was previously shown to be salvaged into water soluble [1] and also into lipidic [2] precursors of phospholipids in stimulated lymphocytes and in lymphoma cells [3]. In this paper we have described that non-dividing murine macrophages salvaged not only 5-3H-CdR but also tritiated thymidine (3H-TdR) mainly into the pools as nucleotides. Chlorpromazine shifted the CdR salvage into a lipidic compound of the cells which was identified as 3H-dCDP-diacylglycerol (dCDP-DAG). After 5-3H-CdR labeling the lipid/DNA ratio was eleven times higher in macrophages than in tonsillar lymphocytes. Thin layer chromatography (TLC) on borate impregnated silica gel plates gave clear separation of CDP-DAG from dCDP-DAG supporting that the extracellular precursor for it is exclusively deoxycytidine and not ribocytidine. No interconversion between deoxy- and and ribocytidine could be observed neither in lymphocytes nor in macrophages.