In vivo responsiveness to glucocorticoid correlated with glucocorticoid receptor content in peripheral blood leukocytes in normal humans.

Dexamethasone loading tests (0.1 mg dexamethasone/kg, iv) were performed in 18 normal males to evaluate the individual responsiveness to glucocorticoid. There were inter-individual differences in increase in peripheral blood polymorphonuclear leukocyte count, decrease in peripheral blood lymphocyte count, and increase in plasma free fatty acids levels after dexamethasone injection. In addition, there was a significant correlation between the maximum increase in polymorphonuclear leukocytes and the maximum decrease in lymphocytes (r = 0.7514, p less than 0.0003). Simultaneous measurements of glucocorticoid receptor content by whole-cell assay revealed that glucocorticoid receptor content in polymorphonuclear leukocytes linearly correlated with that in the corresponding lymphocytes (r = 0.9482, p less than 0.0001). There were also significant correlations between the maximum increase in polymorphonuclear leukocytes and glucocorticoid receptor content in polymorphonuclear leukocytes (r = 0.7239, p less than 0.0007), and between the maximum decrease in lymphocytes and glucocorticoid receptor content in lymphocytes (r = 0.7703, p less than 0.0002). These results suggest that individual differences are preserved both in glucocorticoid responsiveness and in glucocorticoid receptor content in peripheral blood leukocytes in normal humans.