[Effect of inhibitors of polyamine biosynthesis on primary differentiation of mouse egg]

Alpha-Methylornithine, an inhibitor of the synthesis of putrescine does not affect the cleavage of Mouse eggs, cultured in vitro from the 2-cell stage, before blastocyst formation, whereas methylglyoxal-Bis (guanylhydrazone), an inhibitor of the syntheses of spermidine and spermine induces the embryos to become quiescent at about the 8-cell stage; resumption of their development, after transfer to fresh medium, is followed by a delay in cavitation. These results may be related to the biological clock theory for primary differentiation.