Regulation of Glycogen Metabolism
It is important for you to understand that glycogenesis and gluconeogenesis are regulated reciprocally. There is a hormonal regulation system functioning at the muscle and liver level, which regulates the glycogen metabolism. We have studied about the phosphorylation cascade involving the hormones epinephrine and glucagon above. Epinephrine promotes glycogenolysis and inhibits glycogenesis. It stimulates the formation of cAMP by activating adenylate cyclase in the muscle. Insulin, another hormone, increases glycogenesis and decreases glycogenolysis in the muscle. It heightens the entry of glucose unit in the muscle cells. It reduces cAMP levels by speeding up the destruction of cAMP by phosphodiesterase.