DIACYLGLYCEROL FORMATION INDUCED BY HUMAN PLASMIN IN CULTURED ENDOTHELIAL-CELLS

Treatment of cultured bovine carotid artery endothelial cells with 10( -7)M plasmin increased the cellular diacylglycerol which was determine d by the formation of [H-3]palmitate-labeled diacylglycerol and diacyl glycerol mass. Upon the stimulation with plasmin, a gradual increase i n diacylglycerol formation was observed within 20 min then slightly de clined. The maximal effect during the 1-h time course study was 45 and 55% increases in [H-3]palmitate-labeled diacylgycerol and diacylglyce rol mass, respectively, at 20 min after plasmin treatment. Formation o f phosphatidylethanol was also studied in [H-3]palmitate-prelabeled ce lls in the presence of ethanol. Treatment with plasmin for 20 min indu ced a significant 45% increase in phosphatidylethanol formation. The p resent results indicate that the plasmin-induced diacylglycerol format ion in endothelial cells was at least in part mediated through the pho spholipase D activation.