Studies on the effect of normal labour and obstetric analgesia on maternal and cord venous plasma angiotensin converting enzyme activity in primigravidae.
A spectrophotometric (optimized) assay of plasma angiotensin converting enzyme (ACE) activity was carried out in the plasma of primigravid subjects before and after labour; and in the plasma of cord various blood samples obtained from these subjects. The assay was based on the calorimetric determination of hippurate with cyanuric chloride/dioxan reagent, as described by Hurst and Lovell-Smith. The coefficient of variation (CV) for this method during the assay ranged from 7.36% to 8.19% and from 9.20% to 9.79% for the hippurate standards and the control plasma samples respectively. The mean +/- SD of maternal plasma ACE activity before labour and at delivery in the primigravid subjects were 22.23 +/- 4.17 and 16.44 +/- 1.71 units-1 min-1 respectively; while the corresponding value of enzyme activity in the cord venous plasma for these subjects was 15.71 +/- 1.61 unit-1 min-1. Normal labour did not appear to alter significantly the level of maternal and cord venous plasma ACE activity. It would appear that epidural analgesia has a significant effect on the level of maternal plasma ACE activity during labour (x2 = 12.59 P less than 0.05), but not on the cord venous plasma ACE activity.
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Department of Obstetrics and Gynaecology, College of Medicine, Lagos, Nigeria.
Broughton Pipkin
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D015360:Analgesia, Epidural / Q000592:standards*; D016362:Analgesia, Obstetrical / Q000592:standards*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007743:Labor, Obstetric / Q000097:blood*; D007703:Peptidyl-Dipeptidase A / Q000097:blood* / Q000187:drug effects; D011247:Pregnancy; D013053:Spectrophotometry / Q000295:instrumentation / Q000379:methods
D007703:Peptidyl-Dipeptidase A