Hormonal Effects on Differentiation in Neutral Cultures

摘要

The data presented clearly demonstrate that the induction of glycerol phosphate dehydrogenase (GPDH) by cortisol in C6 cells is due to an increased rate of synthesis without alteration of the rate of degradation of the enzyme, thus resulting in a greater number of molecules. Similarly, we have shown by immunotitration, Ouchterlony double diffusion, gel permeation chromatography, pH optimun, heat lability and polyacrylamide gel electrophoresis that GPDH in the brains of normal (induced) and hypophysectomized (uninduced) rats is identical. Thus in vivo as in cell culture, the hormonal regulation of GPDH activity is brought about by a change in the number of molecules, not in their catalytic efficiency. Similar questions now arise about the mRNA for GPDH, i.e., the influence of hydrocortisone on its rate of synthesis and degradation and efficiency of its translation. Since brain GPDH is identical to the enzyme present in muscle and liver, the mechanism for the specificity of the induction is an intrinsic property of brain tissue rather than related to the enzyme itself such as the coding by different structural genes. (ERA citation 03:045371)