Evidence for glucose-6-phosphate transport in rat liver microsomes.
The existence of glucose-6-phosphate transport across the liver microsomal membrane is still controversial. In this paper, we show that S3483, a chlorogenic acid derivative known to inhibit glucose-6-phosphatase in intact microsomes, caused the intravesicular accumulation of glucose-6-phosphate when the latter was produced by glucose-6-phosphatase from glucose and carbamoyl-phosphate. S3483 also inhibited the conversion of glucose-6-phosphate to 6-phosphogluconate occurring inside microsomes in the presence of electron acceptors (NADP or metyrapone). These data indicate that liver microsomal membranes contain a reversible glucose-6-phosphate transporter, which furnishes substrate not only to glucose-6-phosphatase, but also to hexose-6-phosphate dehydrogenase.
Gerin
Isabelle
I
Laboratory of Physiological Chemistry, ICP and Université Catholique de Louvain, Brussels, Belgium.
Van Schaftingen
Emile
E
D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002237:Carbohydrate Dehydrogenases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D019298:Glucose-6-Phosphate / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D051381:Rats
D003509:Cyclohexanecarboxylic Acids; D004791:Enzyme Inhibitors; D026901:Membrane Transport Proteins; C113180:S 3483; D019298:Glucose-6-Phosphate; D002237:Carbohydrate Dehydrogenases; C020552:galactose-6-phosphate dehydrogenase