Effect of interleukin-6/interferon-β2 on glucocorticoid action in rat hepatoma cells☆

Abstract Reuber hepatoma cells (RHC) were treated 4 h with dexamethasone (dex), with and without simultaneous fibroblast-conditioned medium (cIL-6). A cytosol fraction, prepared in the presence of molybdate and dithiothreitol, was analyzed for [ 3 H]dex (20 nM) binding in the presence and absence of 1 μM dex at 4°C. Receptor levels declined from 76.0 fmol/mg at zero dex to 28.8 fmol/mg at 10 nM dex, and to 11.8 fmol/mg at 1 μM dex ( P P ⩽ 0.05), and treatment with cIL-6 alone diminished binding to 9.8 fmol/mg ( P