Inhibition of rat liver glucose-6-phosphate dehydrogenase synthesis by glucagon.

In fasting-refeeding experiments glucagon was found to inhibit the induction of rat liver glucose-6-P dehydrogenase. The kinetics of induction in the presence of glucagon indicated that the hormone decreased the rate of enzyme synthesis without altering the rate of enzyme degradation. Immunochemical titration of the amount of glucose-6-P dehydrogenase protein present in control and glucagon treated rats suggests that glucagon does not produce an inhibited species of the enzyme. Isolation of radioactive glucose-6-P dehydrogenase by precipitation with a specific antiserum provided direct evidence that glucagon inhibited the synthesis of the enzyme. Under identical conditions glucagon had no effect on the levels of 6-phosphogluconate dehydrogenase.