Polyamine levels in rat placenta during pregnancy.

Polyamine levels in rat placenta during pregnancy have been determined. Spermidine and spermine contents are high at the 15th day of gestation, then decrease gradually until to the term, remaining at levels comparable with those occurring in rapid growth tissues. The high levels of spermidine and spermine at 21th day of pregnancy may be related to RNA and protein turnover which is quite elevated at the end of gestation.