Endothelin-1 stimulates cytosolic phospholipase A2 in Chinese hamster ovary cells stably expressing the human ETA or ETB receptor subtype.

ABSTRACT

The ability of endothelin-1 (ET-1) to activate cytosolic phospholipase A2 (cPLA2) has been studied in Chinese Hamster ovary (CHO) cells stably expressing either the human ETA (CHO/ETA) or the human ETB (CHO/ETB) receptor subtype. ET-1 dose-dependently increased a dithiothreitol-insensitive cPLA2 activity in both cell types. In CHO/ETA cells, BQ-123, an ETA-selective antagonist, completely blocked ET-1-induced cPLA2 stimulation. In CHO/ETB cells, the ET-1 response was mimicked by 4AlaET-1 which could be blocked partially by PD 145065, a nonselective antagonist of ETA and ETB. As expected, ET-1 stimulated PGE2 synthesis in CHO cells transfected with ET receptors. We conclude that ET-1 can stimulate cPLA2 via both the human ETA and ETB receptor subtype.