Effect of inhibitors of polyamine synthesis on activation of diapausing mouse blastocysts in vitro

Abstract

Diapausing mouse blastocysts were cultured in vitro with inhibitors of polyamine synthesis and/or the polyamines, putrescine, spermidine and/or spermine. Attachment of blastocysts to the culture dish, the onset of trophoblastic outgrowth and the extent of outgrowth were retarded by methylornithine (10 mM) or methylglyoxal bis-(guanylhydrazone) (50 or 200 μM) and apparently blocked by a combination of these inhibitors. The embryos appeared to make no progress towards activation in the presence of both inhibitors but became active and grew normally when transferred to inhibitor-free medium. The inhibition of growth was also reversed when polyamines (10-5 M) were supplied in the medium along with the inhibitors (P < 0.01). These results suggest that polyamine synthesis is required for activation, growth and development of diapausing blastocysts in vitro.