Prostaglandin production in phenotypically distinct cultured bovine pulmonary artery endothelium.

Bovine pulmonary artery endothelial cells, maintained in culture for prolonged periods, were observed to enter into a secondary growth pattern commonly referred to as sprouting. Our investigations, as well as those of other workers, indicate that these cells represent a phenotypic variant of the original endothelial cell population, rather than the proliferation of a contaminating cell type. A significant increase in prostaglandin production, particularly prostacyclin, could be correlated with the appearance of these phenotypically distinct endothelial cells in culture. We suggest that the elevation in prostacyclin synthesis is a result of endothelial cell sprouting and hypothesize that increased prostacyclin levels may account for the inhibition of platelet deposition reported in post-confluent endothelial cultures.