| Abstract: | Starfish oocyte maturation is triggered by a natural hormone, 1-methyladenine (1-MeAde), produced in the follicle cells, or artificially by dithiothreitol (DTT). These substances act on the oocyte surface to produce a cytoplasmic maturation-promoting factor (MPF), which induces germinal vesicle breakdown (GVBD) and subsequent processes of meiotic maturation. Further, MPF is amplified in immature oocytes that have received the injection of MPF. In this paper the effect of leupeptin and antipain, protease inhibitors of microbial origin, on starfish oocyte maturation was investigated. The protease inhibitors were found to inhibit 1-MeAde-induced maturation when they were applied externally or injected into oocytes. DTT-induced maturation was also inhibited by injection of leupeptin. However, leupeptin did not inhibit the maturation-inducing action of MPF or MPF amplification. These results show that the protease inhibitors suppress the production of MPF by 1-MeAde or DTT, suggesting that some endogenous protease(s) acts in the production of MPF. |
