Up‐regulation of the interleukin‐6‐signal transducing protein (gp130) by interleukin‐6 and dexamethasone in HepG2 cells

Abstract

The hepatic IL-6-receptor is composed of an 80 kDa IL-6-binding protein and a 130 kDa polypeptide (gp130) believed to be involved in signal transduction. Previous experiments have shown that the 80 kDa IL-6-receptor is up-regulated by glucocorticoids, but not by IL-6. Here we demonstrate that IL-6 together with the synthetic glucocorticoid dexamethasone induces the expression of mRNA for gp130 approximately 5-fold in HepG2 cells. The induction was dose- and time-dependent. Dexamethasone alone, interferon-gamma, IL-1 alpha and IL-1 beta had no effect. A possible role for the regulation of the IL-6-signal transducing protein gp130 in various inflammatory states is proposed.