Physiologic role of endogenous human atrial natriuretic peptide in preeclamptic pregnancies

To assess the effect of endogenous human atrial natriuretic peptide on the vascular system in preeclampsia, the circadian variations of plasma human atrial natriuretic peptide, cyclic guanosine 3'5'-monophosphate, cyclic adenosine 3'5'-monophosphate, and blood pressure were measured. In severe preeclamptic women, the mean 24-hour values of human atrial natriuretic peptide and cyclic guanosine 3'5'-monophosphate rose significantly compared with those in normal nonpregnant and pregnant women. Also, in severe preeclamptic women, circadian variations of plasma atrial natriuretic peptide, cyclic guanosine 3'5'-monophosphate, and blood pressure confirmed the same circadian rhythm with acrophase during the middle of the night. Plasma cyclic adenosine 3'5'-monophosphate values did not differ significantly among the three groups and did not confirm a circadian rhythm. These results suggest that plasma human atrial natriuretic peptide may not strongly influence blood pressure, although it may induce the relaxation of vascular smooth muscles via the cyclic guanosine 3'5'-monophosphate system in preeclampsia.