Characterization of aldosterone binding sites in circulating human mononuclear leukocytes

The results indicate that mononuclear leukocytes could be useful for studying the physiological significance of these mineralocorticoid receptors and their regulation in humans.

Abstract

Aldosterone binding sites in human mononuclear leukocytes were characterized after separation of cells from blood by a Percoll gradient. After washing and resuspension in RPMI-1640 medium, cells were incubated at 37 degrees C for 1 h with different concentrations of [3H]aldosterone plus a 100-fold concentration of RU-26988 (11 alpha, 17 alpha-dihydroxy-17 beta-propynylandrost-1,4,6-trien-3-one), with or without an excess of unlabeled aldosterone. Aldosterone binds to a single class of receptors with an affinity of 2.7 +/- 0.5 nM (means +/- SD, n = 14) and a capacity of 290 +/- 108 sites/cell (n = 14). The specificity data show a hierarchy of affinity of desoxycorticosterone = corticosterone = aldosterone greater than hydrocortisone greater than dexamethasone. The results indicate that mononuclear leukocytes could be useful for studying the physiological significance of these mineralocorticoid receptors and their regulation in humans.