Prostaglandin Formation by the Sheep Embryo and Endometrium as an Indication of Maternal Recognition of Pregnancy1

Abstract

Enzymatically dispersed ovine endometrial cells of Days 12, 15, and 20 of pregnancy formed prostaglandins from radioactively labeled arachidonic acid in vitro. The major products were prostacyclin, PGE₂, and PGF_2α. Cells of Day 15 of pregnancy were the most active. Endometrial cells from nonpregnant sheep at Days 12 or 15 of the estrous cycle were unable to form prostaglandins from labeled precursor under the same conditions although the cells concentrated substrate from the incubation medium. In contrast, homogenized endometrium actively metabolized arachidonic acid to prostaglandins.