Platelet-poor plasma serotonin in normal and preeclamptic pregnancy.

We determined serotonin concentrations in platelet-poor plasma (PPP) from 11 preeclamptic pregnant women and 11 normal pregnant women by HPLC with electrochemical detection after a concentration step. Serotonin concentrations in PPP are very low in comparison with those in platelets, so it is very important to avoid in vitro release of serotonin from platelets. We therefore investigated three types of anticoagulants, the method of blood sampling, and the influence of whether the first or second 10 mL of blood is assayed. The type of anticoagulant proved to be important, K3-EDTA giving the best results. The serotonin concentrations in PPP from the preeclamptic pregnant women were significantly higher (P = 0.0001) than in the normal pregnant women: mean values +/- SD were 27.0 +/- 13.5 and 2.8 +/- 1.4 nmol/L, respectively. We suggest that the measurement of serotonin in PPP might be helpful in study of the role of serotonin in the development of preeclampsia.