Dietary induction of glucose-6-phosphate dehydrogenase synthesis.

The effect of dietary carbohydrate on rat liver glucose-6-phosphate dehydrogenase synthesis has been determined by using a method which can accurately quantitate relative rates of synthesis as low as 0.001 percent of total protein synthesis. Hepatocytes were incubated with (3H) leucine for 60 min and G6PD was separated from all other proteins by immunoprecipitation and electrophoresis on two-dimensional O'Farrell gels. The relative rate of synthesis of G6PD increased 70-fold (from 0.0015 to 0.11% of total protein synthesis) in hepatocytes from fasted rats refed a high carbohydrate diet. We have concluded that the 20-30 fold dietary induction of G6PD is due to a 70 and 3 fold increase in synthesis and degradation, respectively.