[Correlation between progesterone and plasminogen activator in rat ovaries during the ovulatory process]

The role of progesterone in the action of hCG on follicular rupture is unclear at present. In this present study, we investigated the correlation between the preovulatory increase in progesterone and the periovulatory increase in plasminogen activator (PA) activities was completely suppressed with simultaneous injection with hCG of a minimum effective dose of cycloheximide to block ovulation completely. Suppression of hCG-induced acute rise of preovulatory progesterone after simultaneous injection with hCG of a minimum effective dose of cyanoketone to block ovulation completely, was accompanied by an only partial but significant suppression of hCG-induced increase in PA activities. Furthermore this suppression of PA activities after concurrent injection of cyanoketone with hCG was reversed by a supplementary injection of a dose of progesterone which was enough to restore ovulatory responses completely against the inhibitory action of cyanoketone. These facts suggest that PA in rat ovaries is synthesized de novo and progesterone may be responsible for the increase of PA in rat ovaries during the periovulatory process.