1446 VASCULAR PROSTAGLANDIN I2 ACTIVITY AS A FUNCTION OF GESTATIONAL AGE

Abstract

PGI2 formation by vascular tissue plays an important role in maintaining the fetal-placental unit. Recently, an abnormality in PGI2 production has been reported in fetal vessels from women with pre-eclampsia, when compared to term deliveries. The gestational ages of the infants evaluated was however <38 wks. (Prostaglandins 20:105, ′80). Since a decrease in PGI2 formation by fetal vessels may be implicated in a variety of placental insufficiency syndromes, it is important to determine if PGI2 production differs in term neonates compared to prematures. We evaluated PGI2 activity from umbilical arteries of infants of various gestational ages in comparison to paired, full term control neonates. Group I consisted of 7 infants (28 to 32 wks) who were compared to simultaneously evaluated 7 term neonates. Group II comprised 8 infants (33 to 36 wks) who were compared to 8 paired term controls. Mean uptake of 14C Arachidonic Acid (A.A.) into the vessels of the term controls and Grp I prematures was similar at 8603 ± 1314 (1SD), and 8555 ± 3281 cpm per 30 mgms tissue. The production of 6-Keto-PGF1α (the end product of PGI2) was similar (4.6 ± 1.7% vs 4.5 ± 1.4%). Values for Grp II prematures were also similar to paired term control values. Uptake of 14C AA into the vascular tissues of the term controls and Grp II prematures were similar at 10170 ± 3059 and 10023 ± 2322 cpm. 6-Keto-PGF1α was also similar at 4.7 ± 0.9%, and 4.8 ± 1.2%. PGI2 activity is not age dependent during the gestational ages of 28 weeks to term.