Catecholamines stimulate glycogenolysis and gluconeogenesis in the liver, causing glucose to be synthesized and released into the blood.Catecholamines stimulate glycogen phosphorylase in muscle to free glucose for use by the muscle. Muscle cannot release glucose into the circulation because it lacks glucose-6-phosphatase. However, the muscle can release lactate, which can be used in gluconeogenesis by the liver.