BSF-2/IL-6, GM-CSF and IL-lfl mRNAs were induced by recombinant IL-I in human astrocytoma cell line U373MG. The induction of BSF-2/IL-6 and IL-lfl mRNAs did not require de novo protein synthesis while that of GM-CSF mRNA required a newly synthesized protein. Dexamethasone inhibited the induction of these cytokine mRNAs by IL-I. This process seems to require continued protein synthesis. These results suggest that the production of these cytokines are positively and negatively controlled by IL-1 and glucocorticoids, respectively, in astrocytes.