Hydrocortisone-induced accumulation of fibronectin mRNA and cell surface-associated fibronectin

A Morris hepatoma 7777-derived cell line, DTH-3, was used to study the control of fibronectin gene expression. In cultures of DTH-3 cells in conventional medium supplemented with serum or in chemically defined MX-83 medium supplemented with insulin no cell surface fibronectin was detectable by indirect immunofluorescence techniques using specific polyclonal antibodies. By Northern blot hybridization analysis a dose- and time-dependent accumulation of 8 kb fibronectin mRNA in response to hydrocortisone treatment was demonstrated. Furthermore, 24 h after addition of hydrocortisone an extensive fibrillar fibronectin network was established. The results suggest that the hydrocortisone-dependent induction of fibronectin production might, at least in part, be controlled at the transcriptional level.