Dexamethasone rapidly reduces the expression of the beta-NGF gene in mouse L-929 cells

Mouse L-929 cells were treated with dexamethasone, and the cellular levels of beta-NGF mRNA were estimated by hybridization of the RNAs with a beta-NGF cDNA probe. The results revealed that the glucocorticoid decreased specifically, in a dose-dependent manner, the pool of beta-NGF transcripts. After 4 h, L-929 cells cultured with 10(-7) M dexamethasone contained one-fifth as much beta-NGF mRNA as untreated control cells, and as little as one-tenth as much when the glucocorticoid concentration was 10(-6) M. The effect of the hormone became maximal after 8 h of treatment. Amounts of beta-NGF secreted by the cells during 24 h were measured with a two-site enzyme immunoassay. They also appeared reduced in cultures exposed to the glucocorticoid. These data indicate that dexamethasone controls negatively the expression of the beta-NGF gene in L-929 cells at some pre-translational level.