Prostacyclin and 51Cr release in cultured human endothelial cells

Conflicting reports have been published concerning the spontaneous release of prostacyclin (PGI2) from endothelial cells and vascular tissue in vitro. In this study the effect of using various incubation medias on the release of PGI2 and 6-keto-PGF1 alpha from primary cultures of confluent endothelial cell monolayers (ECM), grown from human umbilical cord veins, was examined. The incubations were carried out for 5 min at 22 degrees C on a rocker platform. The release of these compounds differed substantially with the various incubation media. Hypotonic and thrombin-containing media produced the greatest release. The 51Cr release from prelabeled ECM was also assayed. A high correlation existed between PGI2, 6-keto-PGF1 alpha and 51Cr occurring in the various media. Since 51Cr release is considered to be a marker of cell membrane damage, the study indicates that under in vitro conditions the amount of PGI2 released is related to the degree of cell injury.