Abstract We examined the effect of millimolar concentrations of the short chain fatty acid, n-butyrate, on the induction of two cytoplasmic enzymes in the C6 rat glioma cell line. Hydrocortisone addition to the culture medium produced a 2- to 3.5-fold induction of glycerol phosphate dehydrogenase after 24 h, and norepinephrine produced a 2-fold increase in lactate dehydrogenase activity in this time period. Five mM sodium butyrate completely abolished the glucocorticoid-mediated response, while the catecholamine-mediated response was unaffected. This selective inhibition was rapid and reversible, and did not affect the level of cytoplasmic steroid binding. Furthermore, high doses of hydrocortisone did not overcome the inhibition. Finally, this phenomenon was also seen in primary cultures of pure oligodendrocytes.