Possible role of glucocorticoid receptors in globin gene expression in differentiating Friend cells.

Previous studies from this laboratory have shown that the expression of globin genes during the dimethyl sulfoxide-induced differentiation of T3C12 Friend erythroleukemia cells in inhibited by dexamethasone and related glucocorticoids. The present report shows that dexamethasone exerts a similar effect on the accumulation of globin mRNA and hemoglobin in differentiating GM86 Friend cells, but that these cells are less sensitive to this hormone. The higher sensitivity of T3C12 cells has been correlated with the presence of 6 times as many cytoplasmic glucocorticoid receptors as in the GM86 cells. The receptors of T3C12 cells have been shown to have properties in common with glucocorticoid receptors found in other tissues. It is proposed that these receptors may be responsible for the steroid control of the globin genes in Friend cells.