Effect of cyclosporin A on carbohydrate metabolism of isolated rat liver cells.
Treatment with cyclosporin A may cause hyperglycemia. The mechanisms for this phenomenon are not entirely clear. The effect of cyclosporin A treatment on rat liver phosphoenolpyruvate-carboxykinase and hepatocyte glycogen synthetase and phosphorylase activity was therefore investigated. Glycogen synthetase (total enzyme activity and the active I-form) was elevated in hepatocytes of rats undergoing immunosuppressive treatment with cyclosporin A. Glycogen phosphorylase activity showed no difference compared to hepatocytes from control rats. Activity of phosphoenolpyruvate-carboxykinase in liver homogenates was significantly enhanced after cyclosporin A treatment. Thus, it appears that cyclosporin A treatment stimulates gluconeogenesis, and glucose is used as substrate for glycogen synthesis in vitro. Differences of in vitro and in vivo experiments might be explained by long-term induction of phosphoenolpyruvate-carboxykinase and the short-term effects of cyclosporin A on glycogen synthetase.
Riegel
W
W
Department of Internal Medicine, University of Freiburg, Federal Republic of Germany.
Stephan
E
E
Balle
C
C
Schollmeyer
P
P
Heidland
A
A
Hörl
W H
WH
D000818:Animals; D002469:Cell Separation; D003524:Cyclosporins / Q000494:pharmacology*; D005260:Female; D006006:Glycogen Synthase / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000201:enzymology*; D010730:Phosphoenolpyruvate Carboxylase / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D003524:Cyclosporins; D006006:Glycogen Synthase; D010730:Phosphoenolpyruvate Carboxylase