Prostacyclin release stimulated by thrombin or bradykinin in porcine endothelial cells cultured from aorta and umbilical vein.

We have investigated the responsiveness of porcine endothelial cells, cultured from aorta or umbilical vein, to bradykinin and thrombin. Aortic cells studied in situ, in primary culture and in subculture responded to both agents with an increase in prostacyclin (PGI2) release; the increase was greater with bradykinin than with thrombin. Umbilical vein cells in primary culture or in subculture also responded to bradykinin and to thrombin; bradykinin was again more effective than thrombin. For both cell types there was a rapid quantitative decline in their ability to be stimulated by either agent with increasing passage number, so that by passage 8 stimulation of PGI2 release could no longer be detected from monolayers cultured under conventional conditions. The presence of a stimulatory response was still, however, easily demonstrable in subcultured cells when they were grown on microcarrier beads, packed in small columns, and perfused. Under these conditions greater than 10-fold stimulation above baseline levels was often found, while the conventional monolayer culture technique gave a smaller maximum stimulation even in primary cultures.