The in vivo regulation of liver and kidney glucose-6-phosphatase by dexamethasone.

The microsomal glucose-6-phosphatase enzyme is situated with its active site inside the lumen of the endoplasmic reticulum and for normal enzyme activity in vivo, transport systems are needed for the substrates and products of the enzyme. Most studies of glucose-6-phosphatase have been carried out on the liver enzyme and relatively little is known about the regulation of the kidney glucose-6-phosphatase enzyme system. Here we demonstrate that the liver and kidney glucose-6-phosphatase systems are regulated differently by dexamethasone and that dexamethasone acts on both the glucose-6-phosphatase enzyme and T1 its associated glucose-6-phosphate transport protein.