Prostaglandin Accumulation by Isolated Uterine Endometrial Epithelial Cells From Six-Day Pregnant Rabbits

Endometrial epithelial cell plaques were enzymatically isolated from rabbit uteri 6 days after artificial insemination. These cells were judged viable by exclusion of [3H]mannitol, trypan blue and [57Co]EDTA, and contained receptors for the ligand, [3H]quinuclidinyl benzilate (QNB). The cell plaques were evaluated for their ability to accumulate prostaglandins (PGs) as a function of PG concentration and type (E2, F2 alpha), temperature, pH, incubation time and cell protein. The PG accumulation was unsaturable, thereby suggesting that the cells, as isolated, and under the conditions of these experiments, do not have identifiable PG receptors or detectable facilitated transport mechanisms. Cells preloaded with PG rapidly released PG after dilution into buffer containing either no or 50 microM unlabeled PG. We suggest that PGs can be accumulated, by endometrial epithelial cells, in the nonionized (nonelectrolyte) form which dissolves (partitions) into the lipid bilayer; the amount of PG accumulated could reflect environmental concentration (levels in the uterine secretions).