Adenylyl cyclase catalyzes the synthesis of camp, and camp hydrolysis is catalyzed by a 5'-phosphodiesterase. if caffeine inhibits 5'-phosphodiesterases, drinking a caffeinated beverage would camp levels and glycogen phosphorylase activity.

Drinking a caffeinated beverage would increase camp levels and increase glycogen phosphorylase activity. Since 5'-phosphodiesterase breaks down camp, blocking the activity of this enzyme would result in an increase of camp levels. Glucogen phosphorylase is an enzyme that catalyzes the hydrolysis of glucogen. An increase in cAMP would result in activation of an enzymatic cascade that involves glucogen phosphorylase.

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