Effects of glucocorticoid hormones on radiation induced and 12-O-tetradecanoylphorbol-13-acetate enhanced radiation transformation in vitro.

We have studied the interactions of glucocorticoid hormones with radiation in the induction of transformation in vitro in C3H10T1/2 cells. We have observed that cortisone has its primary enhancing effect on radiation transformation when present after the radiation exposure during the "expression period", or the time after carcinogen exposure during which promoting agents have been shown to enhance radiation transformation in vitro, and that two different glucocorticoid hormones, dexamethasone and cortisone, have a suppressive effect on the 12-O-tetradecanoylphorbol-13-acetate (TPA) enhancement of radiation transformation in vitro.