We compared the expression of various interferon-gamma (IFN-gamma)-inducible mRNAs in primary rat astrocytes and microglia. Of 11 different mRNAs inducible by IFN-gamma in a macrophage cell line, RAW 264.7, only eight were induced in both types of glia, which included mRNAs encoding the transcriptional factors, IRF-1, LRF-1 and ZIF-268; members of the chemokine family, crg-2/IP-10 and MIG; beta 2-microglobulin and metallothionein-II. The patterns of induction of the mRNAs were more similar between astrocytes and microglia than with RAW 264.7 cells. Comparison of astrocytes from Lewis and Brown Norway rats showed no major differences in the levels of the crg mRNAs or in the amount of Crg-2 protein induced by IFN-gamma.