| Abstract: | Rat renal medullary slices prelabeled with 14C]arachidonic acid generate 14C]diacylglycerol within 1 min of exposure to bradykinin action. Production of 14C]diacylglycerol is transient. 2 min after the addition of bradykinin, the levels of metabolite reach the maximum, but decrease thereafter. Simultaneously, bradykinin induces a parallel decrease of the radioactivity in phosphatidylinositol. No degradation of other phospholipids is observed, and triacylglycerol is not affected. The degradation of 14C]phosphatidylinositol to 14C]diacylglycerol indicated the presence of phospholipase C activity. Preincubation of prelabeled slices with 2 mM dibutyryl cyclic AMP prevents both the generation of diacylglycerol and the degradation of phosphatidylinositol. Neither mepacrine nor indomethacin block diacylglycerol production and phosphatidylinositol breakdown. We conclude that, when rat renal medullary slices are stimulated with bradykinin, phosphatidylinositol-specific phospholipase C is activated. |
