PLASMA AND PLACENTAL CALCITONIN-GENE-RELATED PEPTIDE IN PREGNANCIES COMPLICATED BY SEVERE PREECLAMPSIA

OBJECTIVE: Our purpose was to determine the concentration of calcitoni n gene-related peptide, a potent vasodilator, in maternal plasma, feta l plasma, and placental tissue from pregnancies complicated by severe preeclampsia. STUDY DESIGN: The following groups were studied: severe preeclampsia (group 1, n = 21), normal pregnancies matched for mode of delivery (group 2, n = 21), and nonpregnant women (group 3, n = 17). Maternal venous blood samples were drawn before labor, and fetal venou s samples were drawn from the chorionic plate immediately after delive ry. Calcitonin gene-related peptide was also quantified in placental t issue samples from 15 patients in group 1 and 15 patients in group 2. Calcitonin gene-related peptide was measured with a sensitive and spec ific radioimmunoassay. RESULTS: No differences were found between mate rnal plasma calcitonin gene-related peptide concentrations in groups 1 and 2 (29.8 +/- 4.2 and 30.4 +/- 4.3 pmol/L, respectively). Both had levels similar to those in group 3 (28.5 +/- 5.4 pmol/L). Maternal pla sma concentrations in the preeclamptic group were unchanged 3 days pos t partum (29.1 +/- 3.6 pmol/L). Fetal plasma calcitonin gene-related p eptide concentrations were similar in groups 1 and 2 (30.2 +/- 3.9 and 32.2 +/- 8.8 pmol/L, respectively). A significant correlation was fou nd between maternal and fetal calcitonin gene-related peptide concentr ations (r = 0.43, p < 0.01). Like plasma levels, calcitonin gene-relat ed peptide levels in the supernatants of placental extracts were not d ifferent in preeclamptic and normal pregnancies (108.0 +/- 70.4 and 10 0.9 +/- 56.1 fmol/gm, respectively). CONCLUSION: On the basis of plasm a and placental concentrations, calcitonin gene-related peptide does n ot seem to play an important role in the pathophysiologic mechanisms o f preeclampsia.