Gestational profile of the stimulatory effects of porcine amniotic and allantoic fluids on prostaglandin G/H synthase activity.

The effects of porcine fetal fluids (amniotic and allantoic) on microsomal prostaglandin G/H synthase (PGHS) activity were assessed. Both amniotic and allantoic fluids obtained from late-gestation sows stimulated PGHS activity (as indicated by increased formation of radiolabelled prostaglandin) in a dose-dependent manner. At the maximum dose tested, amniotic and allantoic fluids stimulated prostaglandin (PG) formation by 55.5 +/- 1.5 and 58.5 +/- 4.7%, respectively (n = 3, P less than 0.01). Based upon ED50 values, amniotic fluid was approximately threefold more effective than allantoic fluid in stimulating PG formation. The stimulatory effect of amniotic but not allantoic fluid increased significantly (P less than 0.01) during gestation (Days 47-112). The observed changes in the stimulatory effect of amniotic fluid on microsomal PG formation parallels the in vivo changes that occur in intra-uterine PG synthesis. Amniotic fluid stimulatory activity may contribute to this gestational increase in PG synthesis.