Increased platelet thromboxane A2/prostaglandin H2 receptors in patients with pregnancy induced hypertension.
Pregnancy induced hypertension (PIH) is associated with a variety of disturbances in the hemostatic system including alterations in platelet function, thrombocytopenia, and an increase in platelet turnover. The density of platelet Thromboxane A2 (TXA2)/Prostaglandin H2 (PGH2) receptors was determined in patients with PIH and normal pregnant women, using [125I]-PTA-OH, a TXA2/PGH2 receptor antagonist. The number of platelet TXA2/PGH2 receptors significantly increased (p < 0.008) from 1734 +/- 370 sites/platelet (n = 8) in normal pregnant women to 3703 +/- 846 sites/platelet (n = 9) in patients with severe PIH. The sensitivity of platelets to the TXA2 mimetic U46619 was significantly (p < 0.0005) increased in platelets obtained from severe PIH patients (EC50 = 150 +/- 10nM, n = 3) compared to controls (EC50 = 290 +/- 60 nM, n = 5). These results indicate that an increased number of TXA2/PGH2 receptors as well as increased sensitivity to TXA2/PGH2 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.
Liel
N
N
Department of Medicine, Soroka University Hospital of Kupat-Holim, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Nathan
I
I
Yermiyahu
T
T
Zolotov
Z
Z
Lieberman
J R
JR
Dvilansky
A
A
Halushka
P V
PV
D001792:Blood Platelets / Q000737:chemistry*; D005260:Female; D006801:Humans; D010974:Platelet Aggregation; D010976:Platelet Count; D011225:Pre-Eclampsia / Q000097:blood* / Q000503:physiopathology; D011247:Pregnancy; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology*; D044262:Prostaglandin H2; D011463:Prostaglandins H / Q000502:physiology; D011982:Receptors, Prostaglandin / Q000032:analysis*; D017482:Receptors, Thromboxane / Q000032:analysis* / Q000187:drug effects; D044244:Receptors, Thromboxane A2, Prostaglandin H2; D012720:Severity of Illness Index; D013928:Thromboxane A2 / Q000502:physiology
D011450:Prostaglandin Endoperoxides, Synthetic; D011463:Prostaglandins H; D011982:Receptors, Prostaglandin; D017482:Receptors, Thromboxane; D044244:Receptors, Thromboxane A2, Prostaglandin H2; D044262:Prostaglandin H2; D013928:Thromboxane A2