Objective:This study investigated whether prostaglandin E2 (PGE2) can cross intact fetal membranes in vivo.
Methods:We have developed a novel ovine model using in vivo dialysis systems, positioned between the fetal membranes and decidua and in the amniotic cavity. Sheep were given 25 μCi, 50 ng [3H]PGE2 or 1 mg PGE2 to the amniotic cavity, and radioactivity or PGE2/PGEM concentrations in dialysates were determined.
Results:Endogenous basal PGE2 concentrations were significantly higher iun extra-amniotic than in intra-amniotic dialysates (715 ± 436 versus 80 ± 31 pg/mL; mean ± standard error of the mean; p < .05). After injection of [3]PGE2 into the amniotic cavity, no radioactivity was detected in the extraamniotic dialysate, and this was not influenced by labor induced by ACTH administration to the fetus. In contrast, intra-amniotic injection of 1 mg PGE2 resulted in marked transfer of PEG2 across the fetal membranes to the extra-amniotic dialysis system.
Conclusion:These results suggest that PGE2 can cross the ovine fetal membranes in vivo, escaping metabolism in the chorion.
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