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 associat ion. At maximally effective concentrations, the increase in associatio n was 300-500%. This effect required a preincubation at 37 degrees C f or a minimum of 10 min and was completely reversible after 20-30 min. Steroid treatment increased the rate of toxin-cell association and dec reased the rate of dissociation. The effect was elicited by progestero ne, estradiol, testosterone and diethylstilbestrol, but not by several other steroids tested. Binding of T-2 to isolated ribosomes was not a ltered by the steroids. We speculated that steroids somehow alter the state of ribosomal aggregation or assembly such that more toxin can bi nd after entering the cell.