F. Schneider et al., PLASMA CYCLIC-GMP CONCENTRATIONS AND THEIR RELATIONSHIP WITH CHANGES OF BLOOD-PRESSURE LEVELS IN PREECLAMPSIA, Acta obstetricia et gynecologica Scandinavica, 75(1), 1996, pp. 40-44
Background. One of the possible mechanisms responsible for pre-eclamps
ia is a loss of efficiency of the L-arginine-nitric oxide pathway with
subsequent inactivation of the guanylyl cyclases of the vascular smoo
th muscle cells. As a result there should be a decrease in plasma cycl
ic 3'-5' guanosine monophosphate (cGMP) concentrations in pre-eclampsi
a. We assessed the behavior of this nucleotid in the plasma of pre-ecl
amptic women. Subjects and methods. Sixteen pre-eclamptic women, 16 no
rmotensive pregnant women matched for gestational age and six nonpregn
ant controls were investigated. Arterial blood pressure was recorded a
t inclusion time and then once a-day until the fourth day after delive
ry concomitantly with the collection of blood samples for determining
plasma cGMP, atrial natriuretic peptides (ANP), creatinine, uric acid
and platelet counts. Also 24 h urines were simultaneously collected to
calculate renal clearance of cGMP. Results. Before the initiation of
antihypertensive treatment, plasma cGMP levels were significantly high
er (p<0.01) in pre-eclampsia women as compared both to pregnant normot
ensive controls and nonpregnant women (7.02+/-0.9 versus 4.8+/-0.76 ve
rsus 1.93+/-0.15 pmol . ml(-1), p<0.01). Under antihypertensive treatm
ent, cGMP levels decreased significantly (p<0.05) to 5.48+/-0.9 pmol .
ml(-1). The increase of plasma cGMP was associated with high ANP leve
ls; the likelihood that a renal impairment could account for an increa
se in plasma cGMP was ruled out because the clearance of creatinine wa
s not impaired. Similarly the possibility of a significant linear corr
elation between cGMP levels and blood pressure values or biological da
ta was excluded in these women. Conclusion. Plasma cGMP concentrations
are increased in pre-eclampsia. They decrease to control values when
blood pressure returns to normal values; they indicate enhanced guanyl
yl cyclase activation by ANP and additional factors, but cannot be con
sidered as a direct index of the severity of pre-eclampsia.