Glucocorticoid regulation of metallothionein-I mRNA synthesis in cultured mouse cells.

Eight mouse cell lines were tested for their ability to accumulate metallothionein-I mRNA in response to dexamethasone or cadmium; 5 respond to both inducers, 1 responds to cadmium only, and 2 lymphoid lines respond to neither inducer. The glucocorticoid response was analyzed further using the sarcoma cell line (S180). Metallothionein-I mRNA synthesis increases 5-fold within 1 h of dexamethasone addition and closely parallels the accumulation of nuclear glucocorticoid receptors. Both metallothionein-I mRNA levels and metallothionein synthesis increase coordinately in response to dexamethasone and reach a new steady state by 8 h that is 10-fold higher than control values. Induction of metallothionein-I mRNA appears to be independent of dexamethasone effects on zinc uptake and does not require concomitant protein synthesis.