[Effect of indomethacin on collagenolytic enzyme activities in rabbit ovary]

To investigate the possible participation of prostaglandins in the activation of collagenolytic enzymes of the follicular wall at ovulation, we measured the activities of neutral and acid collagenase in the rabbit ovaries at various stages of follicular development by using synthetic substrate DNP-Pro-Gln-Ile-Ala-Gly-Gln-D-Arg OH (DNP peptide) with its optimal pH 7.6 and alpha-N-benzoyl-DL-arginine-2-naphthylamide HCl (BANA) with pH 6.0, and the effect of ovulation-blocking doses of indomethacin (4 mg/kg) on DNP peptidase and BANA hydrolase activities were investigated. DNP peptidase and BANA hydrolase activities were increased toward ovulation with the highest level 7 to 9hrs after the hCG injection and then decreased significantly at 10hr. At 11hr, around the time of ovulation, the activity stayed at its low level, then rose by 13hr. Following the concomitant administration of IM with hCG, ovulation was blocked and the preovulatory increases in DNP peptidase and BANA hydrolase activities were not observed and their activities stayed at the low level until 20hr. It is suggested that collagenolytic activity for the ovulatory process started to intensiby 6hrs and ended 3hrs prior to ovulation and PGs are necessary for the enzymatic activation of DNP peptidase and BANA hydrolase.