Effect of hydrocortisone on myelin basic protein in developing primary brain cultures.

The hormones hydrocortisone (HC) and triiodothyronine (T3) are known to regulate myelinogenic parameters in cultures of brain cells. However, the effect of glucocorticoids on the myelin-specific metabolite, myelin basic protein, has not been previously studied. In the present studies we show that the concentrations of myelin basic protein (MBP) in developing primary cultures from mouse cerebra are significantly higher in HC (0.3 microM)-treated as compared to untreated cultures after 15 days in vitro. Further, this effect of HC on MBP appears to be T3-dependent. Since HC stimulates oligodendroglia to produce MBP, the effect of HC on the activities of the enzymes, glutamine synthetase which is primarily associated with astrocytes, and acetylcholinesterase, which is primarily associated with neurons was was determined. HC stimulated both enzymes, suggesting that all 3 cell types may be regulated by HC.