Increased platelet thromboxane A2/prostaglandin H2 receptors in patients with pregnancy induced hypertension

Abstract Pregnancy induced hypertension (PIH) is associated with a variety of disturbances in the hemostatic system including alterations in platelet function, thrombocytopenia (1), and an increase in platelet turnover (2,3). The density of platelet Thromboxane A 2 (TXA 2 )/Prostaglandin H2 (PGH2) receptors was determined in patients with PIH and normal pregnant women, using [ 125 I]-PTA-OH, a TXA 2 /PGH 2 receptor antagonist. The number of platelet TXA 2 /PGH 2 receptors significantly increased (p 2 mimetic U46619 was significantly (p 50 =150±10nM, n=3) compared to controls (EC 50 =290±60nM, n=5). These results indicate that an increased number of TXA 2 /PGH 2 receptors as well as increased sensitivity to TXA 2 /PGH 2 mimetics occurs in PIH. Collectively, these results provide further support for the notion that TXA2 and its receptor may play an important role in the pathophysiology of PIH.