Glucose glycogen breakdown

Integration of regulation of glycogen synthesis and glycogen breakdown by glucose... 

It increases glycogen breakdown in liver, resulting in an increased rate of release of glucose by the liver which... 

Net glycogen breakdown enables the liver to secrete glucose to provide for the energy needs of much of the body, particularly the brain. 

Because muscle and adipose tissue lack glucose 6-phosphatase, they cannot convert the glucose 6-phosphate formed by glycogen breakdown to glucose, and these tissues therefore do not contribute glucose to the blood. 

This phosphatase converts phosphorylase a to phosphorylase b, sharply reducing the activity of phosphorylase and slowing glycogen breakdown in response to high blood glucose. Insulin also acts indirectly to stimulate PP1 and slow glycogen breakdown. 

---