[Regulation of glucose-6-phosphate dehydrogenase activity in rat liver by insulin and hydrocortisone]

Activity of glucose-6-phosphate dehydrogenase (G6PD), its isoenzyme spectrum and kinetic properties of the partially purified enzyme were studied in liver tissue of intact rats as well as in animals treated with insulin and hydrocortisone. The data obtained suggest that the activation and inhibition of G6PD by insulin and hydrocortisone, respectively, are due most likely not to alterations in conformation of the enzymatic molecules, but to the opposite influence of these hormones on the content of the main fraction of the isoenzyme spectrum of G6PD, which accounts for 78-90% of its total activity.