Progesterone secretion by the corpus luteum of the early pregnant pig during superfusion in vitro with PGF-2α, LH and oestradiol

Corpora lutea obtained from pregnant sows (Days 18-22) were superfused in vitro for 2-4 h with PGF-2alpha and for 3 h with LH or oestradiol or combinations of PGF-2alpha with LH or oestradiol. LH but not oestradiol stimulated progesterone secretion while superfusion for a minimum of 3 h with PGF-2alpha caused an irreversible decrease in progesterone secretion. LH and PGF-2alpha were mutually antagonistic while oestradiol did not inhibit the luteolytic action of PGF-2alpha.