Objectives.To observe if lysophosphatidic acid（LPA）can influence nuclear nucleoside triphos-phatase（NTPase）activity of isolated hepatocyte from rat

and to investigate the possible mechanisms by which LPA affects the NTPase.Method.Isolated and cultured hepatocytes from rat liver were exposed to LPA（1×10 -9

1×10 -8 and5×10 -8 mol/L）with or without inhibitors of protein kinase C（PKC）and mitogen activating protein kinase kinase（MAPKK）

and the NTPase activity on nuclear envelope was assayed using ATP and GTP as substrate

respectively.Results.Nuclear NTPase activity of rat hepatocytes was potently stimulated by incubation of hepato-cytes with LPA in concentration?and time ?dependent manners.In hepatocytes incubated with LPA

nu-clear NTPase activity was significantly higher than that of the control（P<0.01）.In hepatocytes preincu-bated with PKC inhibitor H-7or MAPKK inhibitor PD98059

LPA-stimulated activation of nuclear NT-Pase was obviously attenuated.In addition

direct incubation of isolated hepatic nuclei with LPA had no effect on nuclear NTPase activity.Conclusion.LPA is involved in modulating nuclear NTPase activity in hepatocytes.The stimulating effect of LPA on the nuclear NTPase is mediated at least partly by PKC and MAPK-dependent pathway.