The detection of spermine and spermidine in human in vitro fertilization supernatants and their relation to early embryo-associated suppressor activity**Supported by grants from Medical Research Council of Canada, Ottawa, Ontario (MA 9707), and National Sciences and Engineering Council (STR 0032764), Ottawa, Ontario, Canada,

Suppressor activity in human IVF supernatants is dependent on the activity of monoamine oxidase present in nonheat-treated FBS and is therefore likely a polyamine. Pooled suppressive growth phase IVF supernatants were concentrated and subjected to HPLC fractionation. The inhibitory peak in the 1,000 to 2,000 d range was neutralized by antibody reactive with spermine and spermidine, and the presence of both polyamines was confirmed by TLC and by ELISA. These data suggest that IVF supernatant polyamines (spermine and spermidine) are responsible for the early embryo-associated suppressor activity correlating with pregnancy success.