ELEVATED LEVELS OF SERUM NITRATE, A STABLE END-PRODUCT OF NITRIC-OXIDE, IN WOMEN WITH PREECLAMPSIA

Objectives Nitric oxide released from vascular endothelial cells is a potent vasodilator and inhibits platelet adhesion. It has been suggest ed that decreased nitric oxide production from dysfunctional endotheli al cells is implicated in the pathophysiology of pre-eclampsia. In thi s study evidence was sought for abnormal production of nitric oxide in pre-eclamptic women. Participants Blood was collected from 20 women p resenting with pre-eclampsia, from 20 matched healthy pregnant control s and from 12 nonpregnant women of childbearing age. Methods Serum nit rate, the stable end metabolite of nitric oxide, was measured by vanad ium III chloride reduction and chemiluminescence. Results Sera from wo men with pre-eclampsia had significantly higher nitrate concentrations (mean 47.4 mu mol/L [SD 13.6]) compared with healthy pregnant (mean 3 1.2 mu mol/L [SD 9.14]) and nonpregnant (mean 32.1 mu mol/L [SD 10.0]) controls. Conclusions These results do not support the hypothesis tha t decreased endothelial cell nitric oxide production may be important in the pathophysiology of pre-eclampsia. On the contrary, serum nitrat e levels are increased which may reflect either increased production o f nitric oxide from an unidentified source or decreased elimination th rough the kidneys.