ATRIAL-NATRIURETIC-PEPTIDE AND VASOACTIVE HORMONES DURING PREECLAMPSIA COMPARED TO NORMAL-PREGNANCY

Objective: To determine whether serial serum sampling throughout the e ntire pregnancy would reveal significant differences in plasma levels of vasoactive agents in preeclampsia compared to normal pregnancy. Met hods: Serial changes in plasma levels of vasoactive agents [atrial nat riuretic peptide (ANP), aldosterone, angiotensin II, cortisol, vasopre ssin, noradrenaline, calcitonin gene related peptide (CGRP), neuropept ide Y (NPY)] were determined in 10 normal and 12 preeclamptic pregnanc ies. We also examined renal (urinary sodium and potassium, osmolarity in plasma and urine, creatinine clearance) and hemodynamic (peripheral resistance, blood volume, total hemoglobin) parameters. Results: Pree clamptic patients had higher plasma levels of ANP (27.2+/- 7.7 vs. 10. 5+/-4 pmol/L, P=0.02), lower levels of the vasodilator CGRP (46.2+/-17 vs. 80.3+/-20 pmol/L, P=0.05), lower levels of aldosterone, and a ten dency to lower levels of angiotensin II and cortisol compared to norma l pregnancies in weeks 29-38. Noradrenaline, vasopressin, and NPY were unaltered. Furthermore, peripheral resistance was increased, blood vo lume was decreased, and total hemoglobin was decreased in the preeclam psia group. Conclusions: High plasma levels of ANP will decrease blood volume by increasing diuresis and extravasation of fluid; low levels of CGRP will increase peripheral resistance and blood pressure. We con clude that these alterations in plasma concentrations of the two vasoa ctive peptides ANP and CGRP may be important in the pathophysiology of preeclampsia.