[Low-affinity binding sites of glucocorticoid].

ABSTRACT

The low-affinity glucocorticoid binding sites (LAGS) with steroid specificity were demonstrated in hepatic cytosol, cerebral cytosol, and thymocytes of rat. The Kd of LAGS was 1-10 mumol.L-1 as estimated by Scatchard, pseudo-scatchard, and competitive analysis. The specific binding of dexamethasone 1-100 nmol.L-1 was roughly parallel with its inhibition of [3H]UdR incorporation in thymocytes of rat, and both were blocked by mifepristone (RU-486), the competitive antagonist of glucocorticoids. These results suggest that the pharmacological activity of glucocorticoid might be mediated at least partially by LAGS.