Glucocorticoid inhibition of 235-1 rat pituitary tumor cell cycle progression.

Control of the cell cycle is accomplished by sequentially activated cyclin-dependent kinases and the action of inhibitory proteins. We have shown that exposure of 235-1 rat pituitary tumor cells to dexamethasone (DEX) leads to a 50% reduction in growth rate. We examined the mechanism by which DEX affects 235-1 cell proliferation by determining the expression levels of proteins involved in cell-cycle progression.