A 27-year-old woman has Type 1 diabetes. Shortly after eating lunch she measures her blood glucose with a glucose meter and finds that it is 340 mg/dL. She administers herself a dose of short-acting insulin. After this injection, which of the following is most likely to be increased in the liver of this woman?

Question

Quizplus · Accepted Answer

Short-acting insulin promotes glycolysis and glycogen synthesis in the liver by increasing the activity of enzymes like phosphofructokinase-1 (PFK1), which is a key regulatory enzyme in glycolysis.  One of the effects of insulin in cells, such as hepatocytes, is the induction of phosphodiesterase, PDE. PDE hydrolyzes cAMP which will lead to reduced activation of PKA. One of the targets of PKA is PFK2. When PFK2 is phosphorylated it hydrolyzes the potent PFK1 activator, fructose- 2,6-bisphosphate (F2,6BP), resulting in reduced activity of PFK1. Conversely, in the presence of insulin PFK2 is not phosphorylated and under these conditions the enzyme synthesizes F2,6BP which results in significant increases in the activity of PFK1

A 27-Year-Old Woman Has Type 1 Diabetes