Interactions of prostaglandins with subpopulations of ovine luteal cells. II. Inhibitory effects of PGF 2α and protection by PGE 2

• Published in: Prostaglandins Vol. 28; no. 1; pp. 127 - 138
• Main Authors: Fitz, T.A., Mock, E.J., Mayan, M.H., Niswender, G.D.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 1984
• ISSN: 0090-6980
• DOI: 10.1016/0090-6980(84)90120-5

Purified preparations of ovine large luteal cells were utilized in a series of experiments to test the effects of prostaglandins (PG) E 2 abd F 2α on cell morphology, viability and secretion of progesterone. Luteal cells were allowed to attach to culture dishes overnight before experiments. In the first series of experiments incubation of large steroidogenic cells with PGF 2α for 6 hr resulted in morphological changes including a retraction of the cell cytoplasm and apparent extrusion of cytoplasmic components which became more pronounced after 12 hr. In a second series of experiments, PGF 2α decreased and PGE 2 increased progesterone accumulation in media after 6 hr when media were not replaced during the incubation period, while progesterone accumulation was not different than that observed in control dishes when both prostaglandins were present. Hourly replacement of the media negated the inhibitory effects of PGF 2α but had no effect on the stimulated secretion of progesterone induced by PGE 2. Finally, in incubations without media replacement, PGF 2α induced a dose-dependent decrease in progesterone accumulation while PGE 2 elicited a biphasic response with progesterone secretion increasing from 0.1 ng/ml to maximal levels at 10 ng/ml followed by a dose-dependent decrease at 100 and 1000 ng/ml. These data are compatible with the hypotheses that: 1) luteolysis is initiated, at least in part, by an action of PGF 2α on large luteal cells; and 2) the embryonic signal from the pregnant uterus which rescues the ovine corpus luteum may be PGE 2.