Changes in nuclear protein pattern by glucocorticoid treatment of lymphoid cells.

ABSTRACT

Glucocorticoids initiate a cytolytic process in lymphoid cells. The ultimate response is preceded by several phenomena. It is generally accepted that these are mediated through messenger proteins. The induction of these proteins is considered the primary effect of glucocorticoids. However, as yet specific gene products have not been identified. In electrophoretic assays, we observed an increased concentration of 6 nuclear proteins within a few hours of exposure of lymphoid cells to glucocorticoids. These proteins displayed prominent DNase activity. However, further studies showed (1) that the proteins concerned are histones, (2) that histones are more easily extracted after glucocorticoid-induced alterations of lymphoid cells, and (3) that basic proteins in general express nuclease activity under certain experimental conditions. This nuclease activity is, however, artifactual. Therefore, though the changes observed are certainly related to glucocorticoid-induced effects, these do not reflect the induction of specific proteins. The results of the study indicate that glucocorticoid-induced changes in the concentration of cellular proteins should be interpreted with caution.