Characterization of the synthesis and release of prolactin by an enriched fraction of human decidual cells.

An enriched fraction of human decidual cells that synthesizes and releases human PRL (hPRL) was obtained by isopycnic centrifugation of collagenase- and hyaluronidase-dispersed cells through Percoll. The cells that synthesized and released hPRL banded at a density of 1.017-1.045 g/ml, an area of the gradient comprising only a small percentage of the total decidual DNA. The enriched cells formed distinct colonies in culture and contained hPRL, as evidenced by indirect immunofluorescent staining with anti-PRL serum. Plated at a density of 5.0 x 10(5) cells/well, the cells produced hPRL at a mean rate of 8.1 +/- 1.1 ng/microgram DNA . 24 h (mean +/- SD) for 8 days. Like decidual explants, the enriched cells responded to phospholipase A2 (0.1 U/ml) with a 54% decrease in hPRL release and to placental conditioned medium (0.5 mg protein/ml medium) with a 62% increase. Insulin (8.3 x 10(-7) M), progesterone (10(-5) - 10(-12) M), and estradiol (10(-5) - 10(-12) M) did not affect hPRL release over 6 days. These results indicate that enriched PRL-releasing cells, obtained by the isopycnic centrifugation of collagenase- and hyaluronidase-dispersed cells, are a useful model for the study of the synthesis and release of PRL.