The polyamines are ubiquitous components of mammalian cells. Those compounds have been postulated to play an important role in different cellular functions including the reorganization of cytoskeleton associated with the cell cycle. In the studies reported here, it was found that inhibitors of polyamine biosynthesis, methylglyoxal-bis[quanylhydrazone] (MGBG) and difluoromethylornithine (DFMO), prevent mitogen-induced accumulation of mRNAs encoding major cytoskeletal components, beta-actin and alpha-tubulin, in mouse splenocytes. These findings suggest mechanisms through which polyamines may exert their effects on the cytoskeleton integrity.