INHIBITION OF CHORION EXPANSION AND PRESERVATION OF FERTILITY IN GOLDFISH (CARASSIUS-AURATUS) EGGS BY PROTEASE INHIBITORS

The in vitro effects of protease inhibitors on chorion expansion and t he fertility of goldfish (Carassius auratus) eggs were investigated. E xpansion of the chorion in ovulated eggs was blocked by the serine pro tease inhibitors benzamidine and soybean trypsin inhibitor when they w ere held in a goldfish Ringer solution. Eggs in which chorion expansio n was inhibited retained their fertility for 30 min when held in this solution. In contrast, ovulated eggs lost their fertility in freshwate r even in the presence of a protease inhibitor. The results suggest th at chorion expansion and loss of fertility in water-activated goldfish eggs may involve proteolysis which was blocked by benzamidine and soy bean trypsin inhibitor. Moreover, the blockage of chorion expansion ma y be pivotal to the preservation of fertility in eggs held in Ringer's solution with soybean trypsin inhibitor. The development of this solu tion provides a means to temporarily hold ovulated goldfish eggs in a viable state outside the female and will permit further studies on fer tilization in this species.