Regulation of mRNAs for three enzymes in the glial cell model C6 cell line.

In the glial cell line C6, regulation of actinomycin D (Act-D)-sensitive translatable polysomal mRNAs of three key enzymes--glycerol phosphate dehydrogenase (GPDH; EC 1.1.1.8) and glutamine synthetase (GS) by glucocorticoids and lactate dehydrogenase (LDH; EC 1.1.1.27) by catecholamines--is described. Though the first two enzymes are hydrocortisone (HC)-inducible, the nature of their response to the hyperacetylating agent sodium butyrate is dramatically different. Furthermore the appearance of GPDH translatable poly(A)+ RNA in HC-induced cells is inhibited by the presence of cycloheximide (CHX), whereas the induction of GS is unaffected by CHX. These observations necessitate further probing into an existing model system to explain the varied mechanisms of induction of these two enzymes by a single inducer. In combination with the third enzyme whose induction by catecholamines is glial specific, we believe that the C6 cell represents the most appropriate cell line for molecular neurobiologists to study the mechanisms of hormone action in glia.