1,2-DIACYLGLYCEROL DOES NOT MEDIATE THE STIMULATORY EFFECT OF PHORBOL 12-MYRISTATE 13-ACETATE ON PHOSPHATIDYLCHOLINE SYNTHESIS IN NIH-3T3 FIBROBLASTS

In HeLa cells, increased 1,2-diacylglycerol (1,2-DAG) has been suggested to mediate the stimulatory effect of phorbol 12-myristate 13-acetate (PMA) on phosphatidylcholine (PtdCho) biosynthesis (A. K. Utal, H. Jamil, and D. E. Vance, 1991, J. Biol. Chem. 266, 24,084-24,091). The aim of this study was to examine if 1,2-DAG might have a similar mediatory role in NIH 3T3 fibroblasts. In these cells, PMA-induced hydrolysis of PtdCho and the formation of secondary product 1,2-DAG was inhibited by exposing the cells to either 300 mm ethanol for 15 min (<80% inhibition) or 43 °C for 60 min (<50% inhibition). In contrast, neither ethanol nor heat-treatment caused significant inhibition of PMA-stimulated PtdCho synthesis. These data indicate that in NIH 3T3 fibroblasts, 1,2-DAG is not a mediator of the stimulatory action of PMA on PtdCho synthesis. © 1992.