INCORPORATION OF ARACHIDONIC AND EICOSAPENTAENOIC ACIDS INTO PHOSPHOLIPIDS OF NONTRANSFORMED AND SPONTANEOUSLY-TRANSFORMED RAT-LIVER EPITHELIAL-CELLS - EFFECTS ON DNA-SYNTHESIS

We compared the incorporation of arachidonic acid (AA) and eicosapenta neoic acid (EPA) into phospholipids of non-transformed (NT-) and spont aneously-transformed (T-) rat liver epithelial cells (RLEC), and their consequences on DNA-synthesis. In NT-cells, both radioactive fatty ac ids were preferentially incorporated into phosphatidylcholine (PC). In T-cells, in contrast, AA was predominantly incorporated into phosphat idylethanolamine (PE), whereas EPA remained preferentially incorporate d into PC. After pulse labelling, we observed in both cell types a pro gressive decrease in AA- and EPA-labelled PC associated with an increa se in AA- and EPA-labelled PE. Preincubation of NT-cells with increasi ng concentrations of AA or EPA (0.1 mu M to 20 mu M) resulted in a con centration-dependent DNA-synthesis stimulation with a stronger effect of AA compared with EPA. In T-cells, the same treatment had no effect on DNA-synthesis.