Effects of steroids on association of T-2 toxin with mammalian cells

The effects of steroids on the association of T-2 toxin with cultured cells were evaluated. Preincubating cells with certain steroids led to a time- and concentration-related increase in total T-2-cell association. At maximally effective concentrations, the increase in association was 300-500%. This effect required a preincubation at 37 degrees C for a minimum of 10 min and was completely reversible after 20-30 min. Steroid treatment increased the rate of toxin-cell association and decreased the rate of dissociation. The effect was elicited by progesterone, estradiol, testosterone and diethylstilbestrol, but not by several other steroids tested. Binding of T-2 to isolated ribosomes was not altered by the steroids. We speculated that steroids somehow alter the state of ribosomal aggregation or assembly such that more toxin can bind after entering the cell.