Blockage of ovulation in the explanted hamster ovary by a collagenase inhibitor

Hamster ovaries explanted at 21:00 h on the day of pro-oestrus were incubated with talopeptin, a potent microbial inhibitor of collagenases, until 10:30 h on the next morning. A talopeptin concentration of 0.16 mM completely blocked ovulation in vitro. The blocking effect decreased markedly in ovaries excised at 23:00 h or later. The results suggest that proteolysis by collagenases is indispensable for the ovulatory process in the hamster.