CHANGES IN SPHINGOSINE CONTENT IN REGENERATING RAT-LIVER CELL-NUCLEI

The sphingosine content in regenerating rat liver cell nuclei was anal yzed by high-performance liquid chromatography during RNA and DNA synt hesis. Experimental activation of nucleic acid synthesis induced sphin gosine accumulation in the cell nuclei. In parallel, induction of the sphingomyelin cycle was observed, involving the activation of sphingom yelinase and changes in sphingomyelin and ceramide contents. The inter action of sphingosine with DNA and the influence of sphingosine on RNA polymerases were studied in vitro to clarify the role of sphingosine in replication and transcription. At a concentration of 10(-4) M, sphi ngosine hindered the interaction of acridine orange with DNA and activ ated transcription enzymes. Several alternative mechanisms for the inv olvement of sphingosine in the regulation of nucleic acid synthesis ar e discussed.