Abstract
Prostacyclin (PGI
2) is a potent vasodilator and inhibitor of platelet aggregation, however, its half-life in aqueous solutions at neutral or acid pH is very short. In this study we have investigated the stability of PGI
2 in plasma from different species and have demonstrated that the half-life of the anti-aggregatory and the hypotensive activity of PGI
2 is considerably prolonged in human plasma. Interestingly the activity of PGI
2 was not maintained on incubation in rat or rabbit plasma indicating that the stabilising factor may be confined to human plasma. Whether such stabilisation prolongs the half-life of PGI
2 in the human circulation merits investigation.