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-PGF_1α 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 °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-PGF_1α 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.