The Effect of Corticosteroid-Binding Globulin on the in Vitro Incorporation of Thymidine into Human Lymphocytes

The purpose of these studies was to examine the inhibitory effect of human corticosteroid-binding globulin (CBG) on the mitogenic effect of phytohemagglutinin on cultured human lymphocytes. We found that CBG could inhibit the incorporation of [14C]thymidine into lymphocytes, but the observed inhibition could be accounted for by the cortisol which was bound to the purified CBG. CBG stripped of cortisol or bound to 11-deoxycortisol was inactive in this assay.