Shingo Kajimura1, Rosemary Foley1, Allan Munck1
1(From the Laboratory of Radiobiology, University of California, San Francisco, California 94143, and the Departments of Medicine and Physiology, Dartmouth Medical School, Hanover, New Hampshire 03755
Tóm tắt
Glucocorticoid binding was measured in resident and thioglycollate-elicited mouse peritoneal macrophages, rabbit alveolar macrophages, and human monocytes. Two assays of binding were used--an assay with intact cells in suspension or monolayers, and an assay of cytosol and nuclear forms of glucocorticoid receptors. The mononuclear phagocytes contained approximately equal to 4--10 X 10(3) high affinity receptor sites per cell, with dissociation constants of approximately equal to 2--8 nM dexamethasone. The binding to the saturable sites was specific for steroids with glucocorticoid or antiglucocorticoid activity. Cortisol, corticosterone, and progesterone competed with dexamethasone for binding, whereas estradiol, dihydrotestosterone, and 11-epicortisol competed very little. Binding of dexamethasone to cytosol and nuclear forms of the receptor complex and temperature-sensitive translocation of cytosol forms to nuclear forms were shown. At 37 degrees C the predominant form of the hormone-receptor complex was nuclear. These results demonstrate that corticosteroids interact with macrophages at physiological concentrations.
