What is the cAMP cascade and where does it occur?

The cAMP cascade describes an intracellular process that occurs upon activation of glucagon and adrenaline receptors. Glucagon receptors are present mainly in the liver, where they activate enzymes that convert glycogen, glycerol, and amino acids to glucose. Thus, the liver is the main place that releases glucose into the blood once a person is in the fasted state. Adrenaline receptors are present throughout the body, and in the heart for example, they respond with the cAMP cascade to result in increased heart rate. A summary of the cascade is as follows:The hormone binds to its receptor -> this activates the enzyme adenylate cyclase -> the enzyme catalyses the following reaction: ATP -> cyclic AMP (cAMP) -> this activates a protein called protein kinase A. This goes on to phosphorylate and thus activate the enzymes in question.