Glucocorticoid Receptors in Human Polymorphonuclear and Mononuclear Leucocytes

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Abstract
Both polymorphonuclear (PMN) and mononuclear (MN) leukocytes constitute targets for glucocorticoid hormones. To comparatively characterize the earliest steps of steroid action in these cell populations, the concentrations and specificities of glucocorticoid receptors in purified human PMN and MN were investigated by a whole-cell binding assay using (3H)dexamethasone as the ligand. PMN and MN contained the same amounts of glucocorticoid receptors (4720 and 4900 receptor sites/cell, respectively). The Kd of the interaction between the cellular receptor and (3H)dexamethasone was .apprxeq. (1 .times. 10-8 M) in both cell populations. No significant differences in the specificities of the steroid binding sites in PMN and MN were found; competition studies revealed the following order of relative binding affinities for a number of compounds: betamethasone > dexamethasone > prednisolone > cortisol > deoxycorticosterone = progesterone > aldosterone > testosterone > estradiol-17.beta.. Known differences in the sensitivities of PMN and MN to glucocorticoids are apparently not caused by differences in the concentrations or characteristics of their glucocorticoid receptors.